Receiving apparatus and decoding method thereof

ABSTRACT

A receiving apparatus includes: a first decoder configured to decode a signal transmitted through a first layer from a layered division multiplexing (LDM) signal using a parity check matrix to generate low density parity check (LDPC) information word bits and parity bits; an encoder configured to encode the LDPC information word bits, generated by decoding the signal transmitted through the first layer, using the parity check matrix to generate parity bits corresponding only to preset columns in the parity check matrix; and a second decoder configured to decode a signal obtained by removing, from the LDM signal, a signal corresponding to the LDPC information word bits generated by decoding the signal transmitted through the first layer, the parity bits generated by the encoder, and the parity bits generated by the first decoder except the parity bits generated by the encoder, thereby to generate information word bits transmitted through a second layer.

CROSS-REFERENCE TO THE RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No.62/243,246 filed on Oct. 19, 2015 and Korean Patent Application No.10-2016-0134560 filed in the Korean Intellectual Property Office on Oct.17, 2016, the disclosures of which are incorporated herein by referencein its entirety.

BACKGROUND

1. Field

Apparatuses and methods consistent with the exemplary embodiments relateto signal reception and decoding, and more particularly, to receivingand decoding a layered division multiplexing (LDM) signal.

2. Description of the Related Art

In the information society of the 21st century, a broadcastingcommunication service is welcoming the time of full-scaledigitalization, multi-channelization, broadband, and high quality. Inparticular, as a supply of high-definition digital television (TV),personal medial player (PMP), and a portable broadcasting device isrecently expanded, a demand for a support of various reception systemsof a digital broadcasting service is also increased.

Meanwhile, since an environment required by a system is diverse such asin the case in which signal latency is important or performance isimportant, it is requested to find a method for processing an LDM signalin the diverse environment.

SUMMARY

Exemplary embodiments may or may not overcome the above disadvantagesand other disadvantages not described above. Also, the exemplaryembodiments are not required to overcome the disadvantages describedabove.

The exemplary embodiments provide a receiving apparatus capable ofefficiently processing an LDM signal, and a decoding method thereof.

According to an exemplary embodiment, there is provided a receivingapparatus receiving and processing a layered division multiplexing (LDM)signal which may include: a first decoder configured to decode a signaltransmitted through a first layer from the LDM signal using a paritycheck matrix to generate low density parity check (LDPC) informationword bits and parity bits; an encoder configured to encode the LDPCinformation word bits, generated by decoding the signal transmittedthrough the first layer, using the parity check matrix to generateparity bits corresponding only to preset columns in the parity checkmatrix; and a second decoder configured to decode a signal obtained byremoving, from the LDM signal, a signal corresponding to the LDPCinformation word bits generated by decoding the signal transmittedthrough the first layer, the parity bits generated by the encoder, andthe parity bits generated by the first decoder except the parity bitsgenerated by the encoder, thereby to generate information word bitstransmitted through a second layer.

The preset columns may be columns having a degree of 1 in the paritycheck matrix.

The parity check matrix may include a first parity check matrixincluding a first information word partial matrix and a first paritypartial matrix, which is a dual diagonal matrix, and a second paritycheck matrix including a second information word partial matrix and asecond parity partial matrix, which is a unit matrix, and the encodermay generate the parity bits corresponding only to the columns havingthe degree of 1 in the parity check matrix.

The first decoder may decode the signal transmitted through the firstlayer from the LDM signal using a first LDPC decoder, and decode theLDPC information word bits, corresponding to the signal transmittedthrough the first layer, using a first Bose, Chaudhuri, Hocquenghem(BCH) decoder to generate information word bits transmitted through thefirst layer.

The encoder may encode the LDPC information word bits, corresponding tothe signal transmitted through the first layer, using an LDPC encoder togenerate the parity bits corresponding only to the preset columns in theparity check matrix.

The encoder may encode the information word bits, transmitted throughthe first layer, using a BCH encoder to generate the parity bits, andthe LDPC encoder may encode the information word bits transmittedthrough the first layer and the BCH parity bits to generate the paritybits corresponding only to the preset columns in the parity checkmatrix.

The second decoder may decode the signal obtained by the removing togenerate LDPC information word bits and parity bits, corresponding to asignal transmitted through the second layer, using the first LDPCdecoder, and decode the LDPC information word bits, corresponding to thesignal transmitted through the second layer, using the first BCH decoderto generate the information word bits transmitted through the secondlayer.

The second decoder may decode the signal obtained by the removing togenerate th LDPC information word bits and parity bits, corresponding toa signal transmitted through the second layer, using a second LDPCdecoder, and decode the LDPC information word bits, corresponding to thesignal transmitted through the second layer, using a second BCH decoderto generate the information word bits transmitted through the secondlayer.

According to an exemplary embodiment, there is provided a decodingmethod of a receiving apparatus receiving and processing an LDM signal.The method may include: decoding a signal transmitted through a firstlayer from the LDM signal using a parity check matrix to generate LDPCinformation word bits and parity bits; encoding the LDPC informationword bits, generated by decoding the signal transmitted through thefirst layer, using the parity check matrix to generate parity bitscorresponding only to preset columns in the parity check matrix; anddecoding a signal obtained by removing, from the LDM signal, a signalcorresponding to the LDPC information word bits generated by decodingthe signal transmitted through the first layer, the parity bitsgenerated by the encoding, and the parity bits generated by the decodingexcept the parity bits generated by the encoding, thereby to generateinformation word bits transmitted through a second layer.

The preset columns may be columns having a degree of 1 in the paritycheck matrix.

The parity check matrix may include a first parity check matrixincluding a first information word partial matrix and a first paritypartial matrix, which is a dual diagonal matrix, and a second paritycheck matrix including a second information word partial matrix and asecond parity partial matrix, which is a unit matrix, and the presetcolumns may have the degree of 1 in the parity check matrix.

In the decoding the signal transmitted through the first layer from theLDM signal, the LDPC information word bits and the parity bitscorresponding to the signal transmitted through the first layer may begenerated using a first LDPC decoder, and the LDPC information wordbits, corresponding to the signal transmitted through the first layer,may be decoded using a first Bose, Chaudhuri, Hocquenghem (BCH) decoderto generate information word bits transmitted through the first layer.

In the generating the parity bits corresponding only to the presetcolumns, the LDPC information word bits, corresponding to the signaltransmitted through the first layer, may be encoded using an LDPCencoder to generate the parity bits corresponding only to the presetcolumn in the parity check matrix.

In the generating the parity bits corresponding only to the presetcolumns, the information word bits, transmitted through the first layer,may be BCH encoded to generate BCH parity bits, and the information wordbits transmitted through the first layer and the BCH parity bits may beencoded to generate the parity bits corresponding only to the presetcolumns in the parity check matrix.

The decoding the signal obtained by the removing may include: generatingLDPC information word bits and parity bits, corresponding to a signaltransmitted through the second layer, using the first LDPC decoder; anddecoding the LDPC information word bits, corresponding to the signaltransmitted through the second layer, using the first BCH decoder togenerate the information word bits transmitted through the second layer.

The decoding the signal obtained by the removing may include: generatingLDPC information word bits and parity bits, corresponding to a signaltransmitted through the second layer, using a second LDPC decoder; anddecoding the LDPC information word bits, corresponding to the signaltransmitted through the second layer, using a second BCH decoder togenerate the information word bits transmitted through the second layer.

According to the exemplary embodiments, the LDM signal may beefficiently processed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The above and/or other aspects will be more apparent by describingcertain exemplary embodiments with reference to the accompanyingdrawings, in which:

FIG. 1 is a block diagram illustrating a configuration of a transmittingapparatus according to an exemplary embodiment;

FIG. 2 is a diagram illustrating an LDPC codeword according to anexemplary embodiment;

FIG. 3 is a diagram illustrating a constellation for an LDM signal;

FIG. 4 is a block diagram illustrating a configuration of a transmittingapparatus according to an exemplary embodiment;

FIG. 5 is a diagram illustrating a structure a parity check matrixaccording to an exemplary embodiment;

FIG. 6 is a block diagram illustrating a configuration of a receivingapparatus according to an exemplary embodiment;

FIGS. 7 and 8 are diagrams illustrating an LDPC decoding;

FIGS. 9 to 22 are block diagrams illustrating a detailed configurationof a receiving apparatus according to various exemplary embodiments; and

FIG. 23 is a flowchart illustrating a decoding method of a receivingapparatus according to an exemplary embodiment.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, the present disclosure will be described in more detailwith reference to the accompanying drawings.

When a receiving apparatus according to an exemplary embodimentprocesses a signal generated according to an LDM system, it may firstdecode a core layer (or an upper layer) signal, inversely restore orgenerate the decoded core layer signal, and remove theinversely-restored or inversely-generated core layer signal from the LDMsignal, thereby making it possible to restore or generated an enhancedlayer (or a lower layer). Hereinafter, the word “restore” may beinterchangeably used with the word “generate.”

A receiving apparatus according to an exemplary embodiment may receiveand process a signal (hereinafter, referred to as a layered divisionmultiplexing (LDM) signal) generated by a superposition coded modulation(SCM) according to the LDM, to thereby restore bits transmitted througheach layer.

Here, the SCM means a coding method in which each of the signalsincluding the same data or different data is superimposed or overlappedto have different power from each other. In this case, a signal having arelatively large power in the LDM signals configures an upper layer (UL)(or core layer), and a signal relatively small power configures a lowerlayer (LL) (or an enhanced layer).

Meanwhile, a transmitting apparatus generating and transmitting the LDMsignal may include components as illustrated in FIG. 1. However, atransmitting apparatus 100 illustrated in FIG. 1 is merely an example,and some of the components illustrated in FIG. 1 may be omitted orcomponents for other processing may be added.

Referring to FIG. 1, the transmitting apparatus 100 may include a firstbit interleaved coded modulation (BICM) encoder 110, a second BICMencoder 120, a first gain controller 130, a second gain controller 140,a time interleaver 150, and an orthogonal frequency divisionmultiplexing (OFDM) transmitter 160.

The first BICM encoder 110 may include a first encoder 111, a first bitinterleaver 112, and a first constellation mapper 113 to encode andinterleave information word bits transmitted through the upper layer(herein, the information word bits, which are data, correspond to the ULsignal of FIG. 1), modulate the encoded and interleaved information wordbits, and map the modulated information word bits to constellationpoints.

In addition, the second BICM encoder 120 may include a second encoder121, a second bit interleaver 122, and a second constellation mapper 123to encode and interleave information word bits transmitted through thelower layer (herein, the information word bits, which are data,correspond to the LL signal of FIG. 1), modulate the encoded andinterleaved information word bits, and map the modulated informationword bits to constellation points.

In this case, the first and second encoders 111 and 121 may include anouter encoder (not shown) and an inner encoder (not shown) to encode theinformation word bits using a concatenated code.

Here, as an outer code performed before an inner code in theconcatenated code, a Bose, Chaudhuri, Hocquenghem (BCH) code may beused, and as the inner code, a low density parity check (LDPC) code maybe used.

To this end, the first and second encoders 111 and 121 may include a BCHencoder (not shown) and an LDPC encoder (not shown).

In this case, the BCH encoder (not shown) may perform BCH encoding forthe information word bits to generate BCH parity bits, and the LDPCencoder (not shown) may perform LDPC encoding for a BCH codewordincluding the information code bits and BCH parity bits, that is, LDPCinformation word bits to generate LDPC parity bits.

An LDPC codeword generated by such encoding may be represented asillustrated in FIG. 2. As illustrated in FIG. 2, the LDPC codeword mayhave a form in which the BCH parity bits and the LDPC parity bits aresequentially added to the information word bits.

Meanwhile, the LDPC encoder (not shown) may encode the LDPC informationword bits according to various code rates to generate the LDPC codewordhaving various lengths.

For example, the LDPC encoder (not shown) may encode the LDPCinformation word bits at the code rates of 3/15, 4/15, 5/15, 6/15, 7/15,8/15, 9/15, 10/15, 11/15, 12/15, and 13/15 to generate the LDPC codewordhaving the length of 16200 or 64800.

Meanwhile, although the example described above illustrates the case inwhich the BCH is used as the outer code, this is merely one example, anda cyclic redundancy check (CRC) code instead of the BCH code may also beused.

In this case, the first and second encoders 111 and 121 may include aCRC encoder (not shown) and an LDPC encoder (not shown).

Specifically, the CRC encoder (not shown) may perform CRC encoding forthe information word bits to generate CRC parity bits, and the LDPCencoder (not shown) may perform LDPC encoding for a CRC codewordincluding the information word bits and CRC parity bits, that is, LDPCinformation word bits to generate LDPC parity bits. The LDPC codewordgenerated by such encoding may have a form in which the CRC parity bitsand the LDPC parity bits are sequentially added to the information wordbits.

According to an exemplary embodiment, however, the first and secondencoders 111 and 121 may or may not include both the BCH encoder (notshown) and the CRC encoder (not shown).

Meanwhile, the first gain controller 130 may adjust power of a signaloutput from the first BICM encoder 110 by multiplying a gain value√{square root over (P_(UL))} with the signal output from the first BICMencoder 110, and may adjust power of a signal output from the secondBICM encoder 120 by multiplying a gain value √{square root over(P_(LL))} with the signal output from the second BICM encoder 120. Inthis case, √{square root over (P_(UL))}²+√{square root over(P_(LL))}₂=1.

In addition, the signal of which the power is adjusted by the first andsecond gain controllers 130 and 140 may be overlapped with each other bythe adder 150, the time interleaver 160 may interleave constellationpoints to which the signal output from the adder 150 is mapped, that is,cells, and the OFDM transmitter 170 may map the interleaved cells to anOFDM frame to transmit the mapped cells to the receiving apparatus 1000.

In this case, one example of the constellation for the LDM signal may berepresented as illustrated in FIG. 3.

FIG. 3 illustrates a case in which the upper layer signal is modulatedwith quadrature phase shift keying (QPSK), and lower layer signal ismodulated with 64-quadrature amplitude modulation (64-QAM), by way ofexample. As such, in the LDM signal, the constellation points for thelower layer signal having the relatively small power are overlapped witheach other based on the constellation points for the upper layer signalhaving the relatively large power.

However, FIG. 3 describes the case in which the upper layer signal ismodulated with the QPSK, and the lower layer signal is modulated withthe 64-QAM, but this is merely one example. That is, the upper layersignal may be modulated with the QPSK, and the lower layer signal mayalso be modulated with 256-QAM.

Meanwhile, FIG. 1 describes the case in which the power for each of thesignal output from the first BICM encoder 110 and the signal output fromthe second BICM encoder 120 is adjusted, and the signals having theadjusted power are then overlapped with each other.

However, as illustrated in FIG. 4, power of a signal output from asecond BICM encoder 120 is first adjusted, the signal having theadjusted power and a signal output from a first BICM encoder 110 areadded by an adder 150, and power of the overlapped signal may be thenadjusted. In this case, a gain value of a first gain controller 130 maybe √{square root over (P_(UL))}, and a gain value of a second gaincontroller 140 may be

$\sqrt{\frac{P_{LL}}{P_{UL}}}.$

Meanwhile, an LDPC encoding process refers to a process of generating anLDPC codeword satisfying H·C^(T)=0 for LDPC information word bits. Here,H denotes a parity check matrix, and C denotes the LDPC codeword. Thatis, the LDPC encoding process refers to a process of generating paritybits in which a summation obtained by multiplying respective columns ofthe parity check matrix with respective LDPC codeword bits becomes a ‘0’vector.

Accordingly, the transmitting apparatus 100 may prestore the paritycheck matrix using a memory (not shown), and LDPC encoders (not shown)of the first and second encoders 111 and 121 may encode the LDPCinformation word bits using the parity check matrix.

Meanwhile, a parity check matrix according to an exemplary embodimentmay have a structure as illustrated in FIG. 5.

The parity check matrix 10 illustrated in FIG. 5 has the same structureas the parity check matrix defined in an advanced television systemcommittee (ATSC) 3.0 standard. Hereinafter, the parity check matrix 10will be schematically described.

The parity check matrix 10, which is a matrix having 0 and 1 as entries,includes a first parity check matrix 20 and a second parity check matrix30.

Here, the first parity check matrix 20 includes a first information wordpartial matrix (i.e., a matrix A) 21 and a first parity partial matrix(i.e., a matrix B) 22, and the second parity check matrix 30 includes asecond information word partial matrix (i.e., a matrix C) 31 and asecond parity partial matrix (i.e., a matrix D) 32.

Specifically, the matrixes A and C are matrixes corresponding to LDPCinformation word bits, wherein the matrix A may include K columns and grows, and the matrix C may include K+g columns and N−k−g rows.

Here, K denotes the number of LDPC information word bits, and N denotesthe number of LDPC codeword bits. In addition, g denotes the number offirst LDPC parity bits, that is, the number of LDPC parity bitscorresponding to the first parity partial matrix 22, and N−k−g denotesthe number of second LDPC parity bits, that is, the number of LDPCparity bits corresponding to the second parity partial matrix 32.

Meanwhile, in the matrixes A and B, positions of the columns and rows atwhich 1 exist may be determined by a code rate and the number of LDPCcodeword bits.

The matrixes B and D are matrixes corresponding to the first LDPC paritybits and the second LDPC parity bits, respectively. That is, the firstLDPC parity bits may be generated based on the matrix B, and the secondLDPC parity bits may be generated based on the matrix D.

Specifically, the matrix B is a dual diagonal matrix including g columnsand g rows. Accordingly, since the number of 1 in the last column of thematrix B is one, and the number of 1 in the remaining columns except forthe last column is two, a degree of the remaining columns except for thelast column in the matrix B is 2, and the degree of the last column is1.

The matrix D is a unit matrix (i.e., an identity matrix) including N-k-gcolumns and N−k−g rows. Accordingly, since the number of 1 in all of thecolumns is one, the degree of all of the columns in the matrix D is 1.

The matrix Z is a zero matrix including N−K−g columns and g rows.Accordingly, all entries of the matrix Z are 0.

Accordingly, the parity check matrix 10 may be defined by the matrixesA, B, C, D, and Z having the forms as described above, and the LDPCencoders (not shown) of the first and second encoders 111 and 121 mayencode the LDPC information word bits using the parity check matrixhaving the structure as illustrated in FIG. 5.

Meanwhile, the receiving apparatus 1000 according to an exemplaryembodiment may receive the LDM signal transmitted by the transmittingapparatus 100 to restore the information word bits transmitted througheach of the layers.

In this case, the receiving apparatus 1000 may restore the informationword bits transmitted through each of the layers using various methods,which will be described in detail below. Hereinafter, the first layerrefers to the upper layer, and the second layer refers to the lowerlayer.

FIG. 6 is a block diagram illustrating a configuration of a receivingapparatus according to an exemplary embodiment.

Referring to FIG. 6, the receiving apparatus 1000 may include a firstdecoder 200, an encoder 300, and a second decoder 400.

The first decoder 200 restores the information word bits transmittedthrough the first layer from the LDM signal.

That is, the first decoder 200 may decode a signal transmitted through afirst layer from an LDM signal using a parity check matrix to restoreLDPC information word bits and LDPC parity bits, and perform BCHdecoding on the LDPC information word bits to restore information wordbits transmitted through the first layer.

Specifically, the first decoder 200 may restore the LDPC informationword bits and the LDPC parity bits which correspond to the signaltransmitted through the first layer from the LDM signal using a firstLDPC decoder (not shown), and may decode the LDPC information word bitsusing a first BCH decoder (not shown) to restore the information wordbits transmitted through the first layer.

Meanwhile, the first decoder 200 may perform the LDPC decoding using theparity check matrix.

Here, the parity check matrix may be the same parity check matrix asthat used when the transmitting apparatus 100 performs LDPC encoding onthe LDPC information word bits to generate the first layer signal. Thatis, the parity check matrix used when the first decoder 200 performs theLDPC decoding may have the same form as the parity check matrix of whenthe LDPC encoder of the first encoder 111 of the transmitting apparatus100 performs the LDPC encoding.

The encoder 300 may encode the LDPC information word bits using a paritycheck matrix to generate LDPC parity bits.

Here, the parity check matrix used by the encoder 300 may be the sameparity check matrix as that used when the transmitting apparatus 100performs the LDPC encoding for the LDPC information word bits togenerate the first layer signal. That is, the parity check matrix usedwhen the encoder 300 performs LDPC encoding may have the same form asthe parity check matrix of when the LDPC encoder of the first encoder111 of the transmitting apparatus 100 performs the LDPC encoding.

In this case, the encoder 300 may encode the LDPC information word bitsusing the parity check matrix to generate all LDPC parity bits.

That is, the encoder 300 may encode the LDPC information word bitsoutput from the first decoder 200 using an LDPC encoder (not shown), tothereby generate first parity bits corresponding to a first paritypartial matrix of a parity check matrix and a second parity bitscorresponding to a second parity partial matrix. Alternatively, theencoder 300 may perform BCH encoding on information word bits restoredby the first decoder 200 using a BCH encoder (not shown) to generate BCHparity bits, and may perform LDPC encoding on LDPC information word bitsincluding the information word bits and the BCH parity bits using anLDPC encoder (not shown) to thereby generate first parity bitscorresponding to the first parity partial matrix of the parity checkmatrix and second parity bits corresponding to the second parity partialmatrix.

Meanwhile, the encoder 300 may also encode the LDPC information wordbits using the parity check matrix to generate some of the LDPC paritybits.

Specifically, the encoder 300 may also encode the LDPC information wordbits using the parity check matrix to generate only the parity bitscorresponding to a preset column in the parity check matrix.

That is, the encoder 300 may encode the LDPC information word bitsoutput from the first decoder 200 using the LDPC encoder (not shown) togenerate the parity bits corresponding to the preset column in theparity check matrix. Alternatively, the encoder 300 may perform the BCHencoding on the information word bits restored by the first decoder 200using the BCH encoder (not shown) to generate the BCH parity bits, andmay perform the LDPC encoding on the LDPC information word bitsincluding the information word bits and the BCH parity bits using theLDPC encoder (not shown) to thereby generate the parity bitscorresponding to the preset columns in the parity check matrix.

Meanwhile, the preset columns may be columns having the degree of 1 inthe parity check matrix.

Accordingly, the encoder 300 may generate parity bits corresponding tothe columns having the degree of 1 in the parity check matrix.

Specifically, referring to FIG. 5, the columns having the degree of 1among 0-th column to an (N−1)-th column of the parity check matrix are a(K+g)-th column to the (N−1)-th column including the matrix Z and thesecond parity partial matrix 32, the encoder 300 may generate only thesecond parity bits corresponding to the columns having the degree of 1.

As such, generating of LDPC parity bits using the encoder 300 is toagain restore the first layer signal.

In order to restore the bits transmitted through the second layer in theLDM system, the first layer signal needs to be removed from the LDMsignal using successive interference cancellation (SIC), and a decodingneeds to be performed for a signal obtained by removing the first layersignal from the LDM signal, that is, the second layer signal.

Accordingly, in order to restore the bits transmitted through the secondlayer, the receiving apparatus 1000 encodes the LDPC information wordbits to generate the LDPC parity bits, and restores the signalcorresponding to the first layer using the LDPC information word bitsand the LDPC parity bits.

The second decoder 400 may restore the information word bits transmittedthrough the second layer from the signal obtained by removing the signalcorresponding to the first layer from the LDM signal.

Here, the signal corresponding to the first layer may be a signalgenerated based on the LDPC information word bits and the LDPC paritybits.

That is, in the case in which the encoder 300 encodes the LDPCinformation word bits to generate all LDPC parity bits, the signalcorresponding to the first layer may be generated based on the LDPCinformation word bits and all the LDPC parity bits generated by theencoding.

However, in the case in which the encoder 300 encodes the LDPCinformation word bits to generate only some of the LDPC parity bits, thesignal corresponding to the first layer may be generated based on theLDPC information word bits generated by the first decoder 200, theremaining parity bits except for the LDPC parity bits generated by theencoder 300 among the LDPC parity bits decoded by the first decoder 200,and the LDPC parity bits generated by the encoder 300.

That is, in the case in which the encoder 300 generates only some of theLDPC parity bits, the receiving apparatus 1000 may generate the signalcorresponding to the first layer using some of the LDPC parity bitsdecoded by the first decoder 200 and the LDPC parity bits generated bythe encoder 300.

Meanwhile, the second decoder 400 may perform decoding using the samedecoder as the first decoder 200 or using a separate decoder.

Specifically, the second decoder 400 may restore LDPC information wordbits and LDPC parity bits which correspond to a signal transmittedthrough a second layer by decoding a signal obtained by removing thesignal corresponding to the first layer from the LDM signal using thefirst LDPC decoder (not shown), and may decode the LDPC information wordbits using the first BCH decoder (not shown) to restore information wordbits transmitted through the second layer.

Here, the first LDPC decoder (not shown) and the first BCH decoder (notshown) may be the decoders used when the first decoder 200 performs thedecoding.

Meanwhile, the second decoder 400 may restore the LDPC information wordbits and the LDPC parity bits which correspond to the signal transmittedthrough the second layer by decoding the signal obtained by removing thesignal corresponding to the first layer from the LDM signal using asecond LDPC decoder (not shown), and may decode the LDPC informationword bits using a second BCH decoder (not shown) to restore theinformation word bits transmitted through the second layer.

Here, the second LDPC decoder (not shown) and the second BCH decoder(not shown) may be separate components which are different from thefirst LDPC decoder (not shown) and the first BCH decoder (not shown)used by the first decoder 200.

Meanwhile, the second decoder 400 may perform the LDPC decoding usingthe parity check matrix.

Here, the parity check matrix may be the same parity check matrix asthat used when the transmitting apparatus 100 performs the LDPC encodingfor the LDPC information word bits to generate the second layer signal.That is, the parity check matrix used when the second decoder 400performs the LDPC decoding may have the same form as the parity checkmatrix of when the LDPC encoder of the second encoder 121 of thetransmitting apparatus 100 performs the LDPC encoding.

Meanwhile, the first and second LDPC decoders (not shown) may decode thebits using an iterative decoding algorithm based on a sum-productalgorithm.

Specifically, the sum-product algorithm is a kind of message passingalgorithm, and the message passing algorithm represents an algorithmthat exchanges messages (e.g., a log likelihood ration (LLR) value)through an edge on a bipartite graph, and calculate an output messagefrom the messages input to a variable node or a check node to update thecalculated output message.

Hereinafter, a decoding method using a message passing operation will bedescribed. However, since the above-mentioned decoding method is alreadyknown, it will be briefly described.

First, FIG. 7 is a diagram illustrating a graph representation method ofan LDPC code.

FIG. 7 is a diagram illustrating an example of a parity check matrix H₁of the LDPC code including four rows and eight columns, and illustratingthe parity check matrix as a tanner graph. Referring to FIG. 7, sincethe parity check matrix H₁ has the eight columns, it generates acodeword having a length of 8, a code generated by H₁ means the LDPCcode, and each of the columns corresponds to encoded 8 bits.

Referring to FIG. 7, the tanner graph of the LDPC code performing anencoding and a decoding based on the parity check matrix H₁ includeseight variable nodes, that is, x₁ (702), x₂ (704), x₃ (706), x₄ (708),x₅ (710), x₆ (712), x₇ (714), and x₈ (716), and four check nodes 718,720, 722, and 724. Here, an i-th column and a j-th row of the paritycheck matrix H₁ of the LDPC code correspond to a variable node x, and aj-th check node, respectively. In addition, a value of 1 of a point atwhich a j-th column and a j-th row of the parity check matrix H₁ of theLDPC code intersect with each other, that is, a value which is not 0,means that there is an edge connecting the variable node xi and the j-thcheck node on the tanner graph as illustrated in FIG. 7.

The degrees of the variable node and the check node in the tanner graphof the LDPC code mean the number of edges connected to the respectivenodes, and this is equal to the number of entries which are not 0 in thecolumn and the row corresponding to the relevant node in the paritycheck matrix of the LDPC code. For example, the degrees of the variablenodes x₁ (702), x₂ (704), x₃ (706), x₄ (708), x₅ (710), x₆ (712), x₇(714), and x₈ (716) in FIG. 7 is sequentially 4, 3, 3, 3, 2, 2, 2, and2, respectively, and the degrees of the check nodes 718, 720, 722, and724 is sequentially 6, 5, 5, and 5, respectively. In addition, thenumber of entries which are not 0 in the respective columns of theparity check matrix H₁ of FIG. 7 corresponding to the variable nodes ofFIG. 7 are sequentially matched to the above-mentioned degrees 4, 3, 3,3, 2, 2, 2, and 2, and the number of entries which are not 0 in therespective rows of the parity check matrix H₁ of FIG. 7 corresponding tothe check nodes of FIG. 7 are sequentially matched to theabove-mentioned degrees 6, 5, 5, and 5.

In this case, a value of an i-th bit may be determined based on amessage of an i-th variable node. Both a hard decision and a softdecision for the value of the i-th bit are possible. Therefore,performance of c_(i), which is the i-th bit of the LDPC codeword maycorrespond to performance of the i-th variable node of the tanner graph,and this may be determined according to a position and the number of 1of the i-th column of the parity check matrix. That is, performance ofbits included in the LDPC codeword depends on the position and thenumber of 1 of the parity check matrix.

Meanwhile, FIG. 8 illustrates a message passing operation which isgenerally used at the time of LDPC decoding, that is, a message passingoperation at any check node and variable node.

A check node m 800 and a plurality of variable nodes 810, 820, 830, and840 connected to the check node m 800 are illustrated in (1) of FIG. 8.In addition, T_(n′,m) illustrated in (1) of FIG. 8 represents a messagepassed from the variable node n′ 810 to the check node 800, and E_(n,m)represents a message passed from the check node m 800 to the variablenode n 830. Here, a collection of all variable nodes connected to thecheck node m 800 is defined as N(m), and a collection that the variablenode n 830 is excluded from N(m) is defined as N(m)\n.

In this case, a message update rule based on the sum-product algorithmmay be represented by the following Mathematical Expression 1.

$\begin{matrix}{{{E_{n,m}} = {\Phi\left\lbrack {\sum\limits_{n^{\prime} \in {{N{(m)}}\backslash \; n}}{\Phi \left( {T_{n^{\prime},m}} \right)}} \right\rbrack}}{{{Sign}\left( E_{n,m} \right)} = {\sum\limits_{n^{\prime} \in {{N{(m)}}\backslash \; n}}{{sign}\left( T_{n^{\prime}m} \right)}}}} & (1)\end{matrix}$

Here, Sign(E_(n,m)) represents a sign of the message E_(n,m), and|E_(n,m)| represents magnitude of the message E_(n,m). Meanwhile, afunction Φ(X) may be represented by the following MathematicalExpression 2.

$\begin{matrix}{{\Phi (x)} = {- {\log\left( {\tan \; {h\left( \frac{x}{2} \right)}} \right)}}} & (2)\end{matrix}$

Meanwhile, a variable node x 850 and a plurality of check nodes 860,870, 880, and 890 connected to the variable node x 850 are illustratedin (2) of FIG. 8. In addition, E_(y′,x) illustrated in (2) of FIG. 8represents a message passed from a check node y′ 860 to the variablenode x 850, and T_(y,x) represents a message passed from the variablenode x 850 to the variable node y 880. Here, a collection of allvariable nodes connected to the variable node x 850 is defined as M(x),and a collection that the check y 880 is excluded from M(m) is definedas M(x)\y.

In this case, a message update rule based on the sum-product algorithmmay be represented by the following Mathematical Expression 3.

$\begin{matrix}{T_{y,x} = {E_{x} + {\sum\limits_{y^{\prime} \in {{M{(x)}}\backslash \; y}}E_{y^{\prime},x}}}} & (3)\end{matrix}$

Here, E_(x) refers to an initial message value of the variable node x.

In addition, when a bit value of the node x is decided, the bit valuemay be represented by the following Mathematical Expression 4.

$\begin{matrix}{P_{x} = {E_{x} + {\sum\limits_{y^{\prime} \in {M{(x)}}}E_{y^{\prime},x}}}} & (4)\end{matrix}$

In this case, a coding bit corresponding to the node x may be decidedaccording to a value of P_(x).

As such, the first and second decoders (not shown) may restore the bitstransmitted through the first and second layers using the passingbetween the variable nodes and the check nodes which are generated basedon the parity check matrix. Here, the number of times the message ispassed between the variable nodes and the check nodes, the number ofiteration times may be preset in the system.

Meanwhile, the receiving apparatus 1000 may further include a tuner (notshown) for receiving the LDM signal transmitted from the transmittingapparatus through a channel, a synchronizer (not shown) forsynchronizing the receiving LDM signal, an equalizer (not shown) forperforming an equalization for the received LDM signal, and a celldemapper (not shown) for demapping the cells from the OFDM frame.

In addition, a signal y_(k) transmitted through a k-th sub-carrier of asymbol of the OFDM frame may be represented as y_(k)=h_(k)(√{square rootover (P_(UL))}x_(kUL)+√{square root over (P_(LL))}x_(kLL))+n_(k). Here,h_(k) denotes a channel for the k-th sub-carrier, n_(k) denotes noisefor the k-th sub-carrier, x_(kUL) denotes a first layer signal mapped tothe k-th sub-carrier, x_(kLL) and denotes a second layer signal mappedto the k-th sub-carrier. Hereinafter, various methods in which theinformation word bits transmitted through the respective layers arerestored by processing the embedded LDM signal will be described in moredetail with reference to the accompanying drawings.

FIG. 9 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 9, a receiving apparatus 1000 may include a timedeinterleaver 911, a first gain controller 912, a first constellationdemapper 913, a bit deinterleaver 914, a first decoder 915, an encoder916, a bit interleaver 917, a constellation mapper 918, a second gaincontroller 919, a delayer 920, an adder 921, a third gain controller922, a second constellation demapper 923, a second bit deinterleaver924, and a second decoder 925.

The time deinterleaver 911 deinterleaves cells demapped from a symbol ofan OFDM frame. Specifically, the time deinterleaver 911, which is aconfiguration corresponding to the time interleaver 160 of thetransmitting apparatus 100 of FIG. 1, may inversely perform theoperation performed by the time interleaver 160. That is, the timedeinterleaver 911 may deinterleave the cells demapped from sub-carriersof the symbol, and may output the deinterleaved cells to the delayer 920and the first gain controller 912.

The first gain controller 912 adjusts power of a signal output from thetime deinterleaver 911.

Specifically, the first gain controller 912, which is a configurationcorresponding to the first gain controller 130 of the transmittingapparatus 100, may multiply a gain value

$\frac{1}{\sqrt{P_{UL}}}$

with the signal output from the time deinterleaver 911 to adjust thepower of the signal output from the time deinterleaver 911, and mayoutput the signal having the adjusted power to the first constellationdemapper 913.

The first constellation demapper 913 may demodulate the signal outputfrom the first gain controller 912, to thereby generate valuescorresponding to the bits transmitted through the first layer.

Specifically, the first constellation demapper 913 may demodulate thesignal output from the first gain controller 912 based on a modulationscheme performed by the first constellation mapper 113 of thetransmitting apparatus 100 to generate the values corresponding to thebits transmitted through the first layer, and may output the values tothe first bit deinterleaver 914.

For example, in the case in which the first constellation mapper 113 ofthe transmitting apparatus 100 performs modulation with the QPSK scheme,the first constellation demapper 913 may demodulate the signal outputfrom the first gain controller 912 using the QPSK scheme, to therebygenerate values corresponding to the bits mapped to the constellationpoints.

Meanwhile, the value corresponding to the bits transmitted from thetransmitting apparatus 100 is typically a value calculated based onpossibility that the received bit is 0 and possibility that the receivedbit is 1, wherein each of the probabilities itself may be used as thevalue corresponding to each of the bits, and as another example, thevalue corresponding to the bits transmitted from the transmittingapparatus 100 may also be an LR or LLR value.

Specifically, the LR value means a ratio of the possibility that the bittransmitted from the transmitting apparatus 100 is 0 and the possibilitythat the bit transmitted from the transmitting apparatus 100 is 1, andthe LLR value may be represented by a value obtained by taking Log tothe ratio of the possibility that the bit transmitted from thetransmitting apparatus 100 is 0 and the possibility that the bittransmitted from the transmitting apparatus 100 is 1.

Meanwhile, although the above-mentioned example describes the case inwhich the LR value or the LLR value is used, this is one example, andthe received signal itself may also be used.

The first bit deinterleaver 914 may deinterleave the signal output fromthe first constellation demapper 913.

Specifically, the first bit deinterleaver 914 may inversely perform theoperation performed by the first bit interleaver 112 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the first decoder 915.

The first decoder 915 may restore the information word bits transmittedthrough the first layer using the values output from the first bitdeinterleaver 914.

To this end, the first decoder 915 may include a first LDPC decoder (notshown) and a first BCH decoder (not shown).

Specifically, the first LDPC decoder (not shown) may perform LDPCdecoding using the values output from the first bit deinterleaver 914using a method corresponding to the LDPC encoding performed by the LDPCencoder (not shown) of the first encoder 111 of the transmittingapparatus 100. That is, the first LDPC decoder (not shown) may performthe LDPC decoding using the values output from the first bitdeinterleaver 914 based on the parity check matrix used when the LDPCencoder (not shown) of the first encoder 111 performs the LDPC encoding,to thereby generate or restore LDPC information word bits and LDPCparity bits from the first layer signal.

In addition, the first BCH decoder (not shown) may perform BCH decodingon the LDPC information word bits decoded by the first LDPC decoder (notshown) using a method corresponding to the BCH encoding performed by theBCH encoder (not shown) of the first encoder 111 of the transmittingapparatus 100, to thereby generate or restore information word bitstransmitted through the first layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

Meanwhile, the encoder 916 may encode the information word bits restoredby the first decoder 915 to generate parity bits.

To this end, the encoder 916 may include an LDPC encoder (not shown) anda BCH encoder (not shown).

Specifically, the BCH encoder (not shown) performs BCH encoding on theinformation word bits using the method performed by the BCH encoder (notshown) of the first encoder 111 of the transmitting apparatus 100 togenerate BCH parity bits.

In addition, the LDPC encoder (not shown) may perform LDPC encoding onthe LDPC information word bits including the information word bits andthe BCH parity bits using the method performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100 togenerate LDPC parity bits, and may output an LDPC codeword including theLDPC information word bits and the LDPC parity bits to the bitinterleaver 917.

In this case, the LDPC encoder (not shown) may encode the LDPCinformation word bits based on the parity check matrix used when theLDPC encoder (not shown) of the first encoder 111 performs the LDPCencoding to generate the LDPC parity bits.

The bit interleaver 917 may interleave the bits output from the encoder916.

Specifically, the bit interleaver 917, which is a configurationcorresponding to the first bit interleaver 112 of the transmittingapparatus 100, may interleave the LDPC codeword output from the encoder916 using the same method as that performed by the first bit interleaver112, and may output the interleaved LDPC codeword bits to theconstellation mapper 918.

The constellation mapper 918 may modulate the bits output from the bitinterleaver 917 to be mapped to constellation points.

Specifically, the constellation mapper 918, which is a configurationcorresponding to the first constellation mapper 113 of the transmittingapparatus 100, may modulate the bits output from the bit interleaver 917using the same method as that performed by the first constellationmapper 113 to be mapped to the constellation points, and may output asignal corresponding to the constellation points to the second gaincontroller 919.

For example, in the case in which the first constellation mapper 113performs the modulation using the QPSK scheme, the constellation mapper918 may modulate the bits output from the bit interleaver 917 with theQPSK scheme.

The second gain controller 919 adjusts power of the signal output fromthe constellation mapper 918.

Specifically, the second gain controller 919, which is a configurationcorresponding to the first gain controller 130 of the transmittingapparatus 100, may multiply a gain value −√{square root over (P_(UL))}with the signal output from the constellation mapper 918 to adjust thepower of the signal output from the constellation mapper 918, and mayoutput a signal having the adjusted power to the adder 923.

The delayer 920 may delay the signal output from the time deinterleaver911 to output the delayed signal.

Specifically, the delayer 922 may delay the signal output from the timedeinterleaver 911 as much as a time (Delay T) obtained by summing alltimes taken to perform a signal processing at the first constellationdemapper 913, the first bit deinterleaver 914, the first decoder 915,the encoder 916, the bit interleaver 917, and the constellation mapper918 to output the delayed signal to the adder 921.

The adder 921 may sum the signal output from the delayer 920 and thesignal output from the second gain controller 919, and may output asummed signal to the third gain controller 922. Accordingly, the signaloutput from the adder 921 may be a signal obtained by removing the firstlayer signal from the LDM signal, that is, the second layer signal.

The third gain controller 922 adjusts power of the signal output fromthe adder 921.

Specifically, the third gain controller 922, which is a configurationcorresponding to the second gain controller 140 of the transmittingapparatus 100, may multiply a gain value

$\frac{1}{\sqrt{P_{LL}}}$

with the signal output from the adder 921 to adjust the power of thesignal output from the adder 921, and may output a signal having theadjusted power to the second constellation demapper 923.

The second constellation demapper 923 may demodulate the signal outputfrom the third gain controller 922, to thereby generate valuescorresponding to the bits transmitted through the second layer.

Specifically, the second constellation demapper 923 may demodulate thesignal output from the third gain controller 922 based on the modulationscheme performed by the second constellation mapper 123 of thetransmitting apparatus 100 to generate the values corresponding to thebits transmitted through the second layer, and may output the values tothe second bit deinterleaver 924.

For example, in the case in which the second constellation mapper 123 ofthe transmitting apparatus 100 performs the modulation with the 64-QAMscheme, the second constellation demapper 923 may demodulate the signaloutput from the third gain controller 922 using the 64-QAM scheme, tothereby generate values corresponding to the bits mapped to theconstellation points. As another example, in the case in which thesecond constellation mapper 123 of the transmitting apparatus 100performs the modulation with the 256-QAM scheme, the secondconstellation demapper 923 may demodulate the signal output from thethird gain controller 922 using the 256-QAM scheme, to thereby generatethe values corresponding to the bits mapped to the constellation points.

The second bit deinterleaver 924 may deinterleave the signal output fromthe second constellation demapper 923.

Specifically, the second bit deinterleaver 924 may inversely perform theoperation performed by the bit interleaver 122 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the second decoder 925.

The second decoder 925 may restore the information word bits transmittedthrough the second layer using the values output from the second bitdeinterleaver 924.

To this end, the second decoder 925 may include a second LDPC decoder(not shown) and a second BCH decoder (not shown).

Specifically, the second LDPC decoder (not shown) may perform LDPCdecoding using the values output from the second bit deinterleaver 924using a method corresponding to the LDPC encoding performed by the LDPCencoder (not shown) of the second encoder 121 of the transmittingapparatus 100. That is, the second LDPC decoder (not shown) may performLDPC decoding using the values output from the second bit deinterleaver924 based on the parity check matrix used when the LDPC encoder (notshown) of the second encoder 121 performs the LDPC encoding, to therebyrestore LDPC information word bits and LDPC parity bits from the secondlayer signal.

In addition, the second BCH decoder (not shown) may perform BCH decodingon the LDPC information word bits decoded by the LDPC decoder (notshown) using a method corresponding to the BCH encoding performed by theBCH encoder (not shown) of the second encoder 121 of the transmittingapparatus 100, to thereby restore information word bits transmittedthrough the second layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

Meanwhile, although the above-mentioned example describes the case inwhich each of the first and second layer signals is processed using twoforward error correction (FEC) blocks, the first and second layersignals may also be processed using one FEC block according to anexemplary embodiment. That is, the receiving apparatus 1000 may notseparately include an LDPC decoder and a BCH decoder for processing eachof the first layer signal and the second layer signal, but may perform atime-division processing for the first layer signal and the second layersignal using one LDPC decoder and one BCH decoder to decode theinformation word bits from the first layer signal and the second layersignal.

Here, a method for processing the first and second layer signals usingone FEC block will be described in more detail with reference to FIG.10.

FIG. 10 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 10, a receiving apparatus 1000 may include a buffer1011, a time deinterleaver 1012, a first gain controller 1013, a dataselector 1014, a constellation demapper 1015, a bit deinterleaver 1016,a decoder 1017, an encoder 1018, a bit interleaver 1019, a constellationmapper 1020, a second gain controller 1021, a delayer 1022, an adder1023, and a third gain controller 1024.

The buffer 1011 may store an LDM signal including a first layer signaland a second layer signal, and may sequentially output the LDM signal.

Specifically, the buffer 1011 may output the first layer signal and thesecond layer signal mapped to a k-th sub-carrier of a symbol of an OFDMframe to the time deinterleaver 1012, and may output the first layersignal and the second layer signal mapped to a (k+1)-th sub-carrier wheninformation word bits are decoded from each of the first layer signaland the second layer signal mapped to the k-th sub-carrier byconsidering a time for which the information word bits are decoded fromeach of the first layer signal and the second layer signal,

The time deinterleaver 1012 may deinterleave the signal output from thebuffer 1011. Specifically, the time deinterleaver 1012, which is aconfiguration corresponding to the time interleaver 160 of thetransmitting apparatus 100 of FIG. 1, may inversely perform theoperation performed by the time interleaver 160. That is, the timedeinterleaver 1012 may deinterleave cells demapped from the sub-carriersof the symbol, and may output the deinterleaved cells to the first gaincontroller 1013 and the delayer 1022.

The first gain controller 1013 adjusts power of a signal output from thetime deinterleaver 1012.

Specifically, the first gain controller 1013, which is a configurationcorresponding to the first gain controller 130 of the transmittingapparatus 100, may multiply a gain value

$\frac{1}{\sqrt{P_{UL}}}$

with the signal output from the time deinterleaver 1012 to adjust thepower of the signal output from the time deinterleaver 1012, and mayoutput a signal having the adjusted power to the data selector 1014.

The data selector 1014 may receive the signals output from the firstgain controller 1013 and the third gain controller 1024, and may selectone of the signals to be output.

Specifically, in the case in which the first layer signal is to bedecoded, the data selector 1014 may output the signal received from thefirst gain controller 1013 to the constellation demapper 1015.

The constellation demapper 1015 may demodulate the signal output fromthe data selector 1014, to thereby generate values corresponding to bitstransmitted through each of the first layer and the second layer.

Specifically, in the case in which the first layer signal is to bedecoded, the constellation demapper 1015 may demodulate the signaloutput from the data selector 1014 based on a modulation schemeperformed by the first constellation mapper 113 of the transmittingapparatus 100 to generate values corresponding to the bits transmittedthrough the first layer, and may output the values to the bitdeinterleaver 1016.

For example, in the case in which the first constellation mapper 113 ofthe transmitting apparatus 100 performs modulation with the QPSK scheme,the constellation demapper 1015 may demodulate the signal output fromthe data selector 1014 using the QPSK scheme, to thereby generate valuescorresponding to the bits mapped to the constellation points.

Meanwhile, the value corresponding to the bits transmitted from thetransmitting apparatus 100 is typically a value calculated based onpossibility that the received bit is 0 and possibility that the receivedbit is 1, wherein each of the probabilities itself may be used as thevalue corresponding to each of the bits, and as another example, thevalue corresponding to the bits transmitted from the transmittingapparatus 100 may also be an LR or LLR value.

Specifically, the LR value means a ratio of the possibility that the bittransmitted from the transmitting apparatus 100 is 0 and the possibilitythat the bit transmitted from the transmitting apparatus 100 is 1, andthe LLR value may be represented by a value obtained by taking Log tothe ratio of the possibility that the bit transmitted from thetransmitting apparatus 100 is 0 and the possibility that the bittransmitted from the transmitting apparatus 100 is 1.

Meanwhile, although the above-mentioned example describes the case inwhich the LR value or the LLR value is used, this is one example, andthe received signal itself may also be used.

The bit deinterleaver 1016 may deinterleave the signal output from theconstellation demapper 1015.

Specifically, in the case in which the first layer signal is decoded,the bit deinterleaver 1016 may inversely perform the operation performedby the first bit interleaver 112 of the transmitting apparatus 100, tothereby deinterleave the value corresponding to the bits and to outputthe deinterleaved values to the decoder 1017.

The decoder 1017 may restore information word bits transmitted throughthe first layer using the values output from the bit deinterleaver 1016.

To this end, the decoder 1017 may include an LDPC decoder (not shown)and a BCH decoder (not shown).

Specifically, the LDPC decoder (not shown) may perform LDPC decodingusing the values output from the bit deinterleaver 1016 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100. Thatis, the LDPC decoder (not shown) may perform the LDPC decoding using thevalues output from the bit deinterleaver 1016 based on the parity checkmatrix used when the LDPC encoder (not shown) of the first encoder 111performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the first layer signal.

In addition, the BCH decoder (not shown) may perform BCH decoding on theLDPC information word bits decoded by the LDPC decoder (not shown) usinga method corresponding to the BCH encoding performed by the BCH encoder(not shown) of the first encoder 111 of the transmitting apparatus 100,to thereby restore information word bits transmitted through the firstlayer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

Meanwhile, the encoder 1018 may encode the information word bitsrestored by the decoder 1017 to generate parity bits.

To this end, the encoder 1018 may include an LDPC encoder (not shown)and a BCH encoder (not shown).

Specifically, the BCH encoder (not shown) performs BCH encoding on theinformation word bits using the method performed by the BCH encoder (notshown) of the first encoder 111 of the transmitting apparatus 100 togenerate BCH parity bits.

In addition, the LDPC encoder (not shown) may perform LDPC encoding onthe LDPC information word bits including the information word bits andthe BCH parity bits using the method performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100 togenerate LDPC parity bits, and may output an LDPC codeword including theLDPC information word bits and the LDPC parity bits to the bitinterleaver 1019.

In this case, the LDPC encoder (not shown) may encode the LDPCinformation word bits based on the parity check matrix used when theLDPC encoder (not shown) of the first encoder 111 performs the LDPCencoding to generate the LDPC parity bits.

The bit interleaver 1019 may interleave the bits output from the encoder1018.

Specifically, the bit interleaver 1019, which is a configurationcorresponding to the first bit interleaver 112 of the transmittingapparatus 100, may interleave the LDPC codeword output from the encoder1018 using the same method as that performed by the first bitinterleaver 112, and may output the interleaved LDPC codeword bits tothe constellation mapper 1020.

The constellation mapper 1020 may modulate the bits output from the bitinterleaver 1019 to be mapped to constellation points.

Specifically, the constellation mapper 1020, which is a configurationcorresponding to the first constellation mapper 113 of the transmittingapparatus 100, may modulate the bits output from the bit interleaver1019 using the same method as that performed by the first constellationmapper 113 to be mapped to the constellation points, and may output asignal corresponding to the constellation points to the second gaincontroller 1021.

For example, in the case in which the first constellation mapper 111performs the modulation using the QPSK scheme, the constellation mapper1020 may modulate the bits output from the bit interleaver 1019 with theQPSK scheme.

The second gain controller 1021 adjusts power of the signal output fromthe constellation mapper 1020.

Specifically, the second gain controller 1021, which is a configurationcorresponding to the first gain controller 130 of the transmittingapparatus 100, may multiply a gain value −√{square root over (P_(UL))}with the signal output from the constellation mapper 1020 to adjust thepower of the signal output from the constellation mapper 1020, and mayoutput a signal having the adjusted power to the adder 1023.

The delayer 1022 may delay the signal output from the time deinterleaver1012 to output the delayed signal.

Specifically, the delayer 1022 may delay the signal output from the timedeinterleaver 1015 as much as a time (Delay T) obtained by summing alltimes taken to perform a signal processing at the constellation demapper1015, the bit deinterleaver 1016, the decoder 1017, the encoder 1018,the bit interleaver 1019, and the constellation mapper 1020 to outputthe delayed signal to the adder 1023.

The adder 1023 may sum the signal output from the delayer 1022 and thesignal output from the second gain controller 1021, and may output asummed signal to the third gain controller 1024. Accordingly, the signaloutput from the adder 1023 may be a signal obtained by removing thefirst layer signal from the LDM signal, that is, the second layersignal.

The third gain controller 1024 adjusts power of the signal output fromthe adder 1023.

Specifically, the third gain controller 1024, which is a configurationcorresponding to the second gain controller 140 of the transmittingapparatus 100, may multiply a gain value

$\frac{1}{\sqrt{P_{LL}}}$

with the signal output from the adder 1023 to adjust the power of thesignal output from the adder 1023, and may output a signal having theadjusted power to the date selector 1014.

The data selector 1014 may receive the signals output from the firstgain controller 1013 and the third gain controller 1024, and may selectone of the signals to be output.

Specifically, in the case in which the second layer signal is to bedecoded, the data selector 1024 may output the signal received from thethird gain controller 1024 to the constellation demapper 1015.

The constellation demapper 1015 may demodulate the signal output fromthe data selector 1014, to thereby generate values corresponding to thebits transmitted through each of the layers.

Specifically, in the case in which the second layer signal is to bedecoded, the constellation demapper 1015 may demodulate the signaloutput from the data selector 1014 based on the modulation schemeperformed by the second constellation mapper 123 of the transmittingapparatus 100 to generate values corresponding to the bits transmittedthrough the second layer, and may output the values to the bitdeinterleaver 1016.

For example, in the case in which the second constellation mapper 123 ofthe transmitting apparatus 100 performs the modulation with the 64-QAMscheme, the constellation demapper 1015 may demodulate the signal outputfrom the data selector 1014 using the 64-QAM scheme, to thereby generatevalues corresponding to the bits mapped to the constellation points. Asanother example, in the case in which the second constellation mapper123 of the transmitting apparatus 100 performs the modulation with the256-QAM scheme, the constellation demapper 1015 may demodulate thesignal output from the data selector 1014 using the 256-QAM scheme, tothereby generate values corresponding to the bits mapped to theconstellation points.

The bit deinterleaver 1016 may deinterleave the signal output from theconstellation demapper 1015.

Specifically, in the case in which the second layer signal is to bedecoded, the bit deinterleaver 1016 may inversely perform the operationperformed by the bit interleaver 122 of the transmitting apparatus 100,to thereby deinterleave the value corresponding to the bits and tooutput the deinterleaved values to the decoder 1017.

The decoder 1017 may restore the information word bits transmittedthrough the second layer using the values output from the bitdeinterleaver 1016.

In this case, the decoder 1017 may perform decoding using the LDPCdecoder (not shown) and the BCH decoder (not shown).

Specifically, the LDPC decoder (not shown) may perform LDPC decodingusing the values output from the bit deinterleaver 1016 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the second encoder 121 of the transmitting apparatus 100. Thatis, the LDPC decoder (not shown) may perform the LDPC decoding using thevalues output from the bit deinterleaver 1016 based on the parity checkmatrix used when the LDPC encoder (not shown) of the second encoder 121performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the second layer signal.

In addition, the BCH decoder (not shown) may perform BCH decoding on theLDPC information word bits decoded by the LDPC decoder (not shown) usinga method corresponding to the BCH encoding performed by the BCH encoder(not shown) of the second encoder 121 of the transmitting apparatus 100,to thereby restore information word bits transmitted through the secondlayer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

As described above, according to an exemplary embodiment, since separateFEC blocks for processing each of the layer signals are not used, buteach of the layer signals is processed using one FEC block, complexitymay be reduced in view of hardware.

Meanwhile, although FIGS. 9 and 10 describe the cases in which in orderto restore the first layer signal, the BCH parity bits are generated byperforming the BCH encoding on the information word bits restored fromthe received first layer signal, the LDPC parity bits are generated byperforming the LDPC encoding the LDPC information word bits includingthe information word bits and the BCH parity bits, and the signalcorresponding to the first layer is restored using the LDPC informationword bits and the LDPC parity bits, this is merely one example.

That is, the receiving apparatus 1000 may also restore the signalcorresponding to the first layer by performing only the LDPC encoding.

Specifically, the receiving apparatus 1000 may generate the LDPC paritybits by performing the LDPC encoding on the LDPC information word bitsdecoded from the first layer signal without separately performing theBCH encoding, and may restore the signal corresponding to the firstlayer using the LDPC information word bits and the LDPC parity bits.

Hereinafter, a more detailed description thereof will be provided withreference to FIGS. 11 and 12.

FIG. 11 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 11, a receiving apparatus 1000 may include a timedeinterleaver 1111, a first gain controller 1112, a first constellationdemapper 1113, a bit deinterleaver 1114, a first LDPC decoder 1115-1, afirst BCH decoder 1115-2, an LDPC encoder 1116, a bit interleaver 1117,a constellation mapper 1118, a second gain controller 1119, a delayer1120, an adder 1121, a third gain controller 1122, a secondconstellation demapper 1123, a second bit deinterleaver 1124, and asecond decoder 1125.

Meanwhile, since the time deinterleaver 1111, the first gain controller1112, the first constellation demapper 1113, the bit deinterleaver 1114,the bit interleaver 1117, the constellation mapper 1118, the second gaincontroller 1119, the delayer 1120, the adder 1121, the third gaincontroller 1122, the second constellation demapper 1123, the second bitdeinterleaver 1124, and the second decoder 1125 illustrated in FIG. 11perform the same operations as the time deinterleaver 911, the firstgain controller 912, the first constellation demapper 913, the bitdeinterleaver 914, the bit interleaver 917, the constellation mapper918, the second gain controller 919, the delayer 920, the adder 921, thethird gain controller 922, the second constellation demapper 923, thesecond bit deinterleaver 924, and the second decoder 925 described inFIG. 9, a detailed description thereof will be omitted.

However, since the signal corresponding to the first layer is restoredby performing only the LDPC encoding in FIG. 11, the delayer 1120 delaysthe signal output from the time deinterleaver 1111 as much as a time(Delay T) obtained by summing all times taken to perform signalprocessing at the first constellation demapper 1113, the first bitdeinterleaver 1114, the first LDPC decoder 1115, the LDPC encoder 1116,the bit interleaver 1117, and the constellation mapper 1118.

Meanwhile, the first LDPC decoder 1115-1 may perform LDPC decoding usingthe values output from the first bit deinterleaver 1114 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100. Thatis, the first LDPC decoder 1115-1 may perform the LDPC decoding usingthe values output from the first bit deinterleaver 1111 based on theparity check matrix used when the LDPC encoder (not shown) of the firstencoder 111 performs LDPC encoding, to thereby restore LDPC informationword bits and LDPC parity bits from the first layer signal.

In addition, the first BCH decoder 1115-2 may perform BCH decoding onthe LDPC information word bits restored by the first LDPC decoder 1115-1with a scheme corresponding to the BCH encoding performed by the BCHencoder (not shown) of the first encoder 111 of the transmittingapparatus 100, to thereby restore information word bits transmittedthrough the first layer.

Meanwhile, the LDPC encoder 1116 may encode the LDPC information wordbits restored by the first LDPC decoder 1115-1 to generate LDPC paritybits.

Specifically, the LDPC encoder 1116 may perform LDPC encoding on theLDPC information word bits by the LDPC encoding performed by the LDPCencoder (not shown) of the first encoder 111 of the transmittingapparatus 100 to generate the LDPC parity bits, and may output an LDPCcodeword including the LDPC information word bits and the LDPC paritybits to the bit interleaver 1117.

In this case, the LDPC encoder 1116 may encode the LDPC information wordbits based on the parity check matrix used when the LDPC encoder (notshown) of the first encoder 111 performs the LDPC encoding to generatethe LDPC parity bits.

FIG. 12 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 12, a receiving apparatus 1000 may include a buffer1211, a time deinterleaver 1212, a first gain controller 1213, a dataselector 1214, a constellation demapper 1215, a bit deinterleaver 1216,an LDPC decoder 1217-1, a BCH decoder 1217-2, an LDPC encoder 1218, abit interleaver 1219, a constellation mapper 1220, a second gaincontroller 1221, a delayer 1222, an adder 1223, and a third gaincontroller 1224.

Meanwhile, since the buffer 1211, the time deinterleaver 1212, the firstgain controller 1213, the data selector 1214, the constellation demapper1215, the bit deinterleaver 1216, the bit interleaver 1219, theconstellation mapper 1220, the second gain controller 1221, the delayer1222, the adder 1223, and the third gain controller 1224 illustrated inFIG. 12 perform the same operations as the buffer 1011, the timedeinterleaver 1012, the first gain controller 1013, the data selector1014, the constellation demapper 1015, the bit deinterleaver 1016, thebit interleaver 1019, the constellation mapper 1020, the second gaincontroller 1021, the delayer 1022, the adder 1023, and the third gaincontroller 1024 described in FIG. 10, a detailed description thereofwill be omitted.

However, since the signal corresponding to the first layer is restoredby performing only the LDPC encoding in FIG. 12, the delayer 1222 delaysthe signal output from the time deinterleaver 1212 as much as a time(Delay T) obtained by summing all times taken to perform a signalprocessing at the constellation demapper 1215, the bit deinterleaver1216, the LDPC decoder 1217-1, the LDPC encoder 1218, the bitinterleaver 1219, and the constellation mapper 1220.

Meanwhile, in the case in which the first layer signal is restored, theLDPC decoder 1217-1 and the BCH decoder 1217-2 may restore informationword bits transmitted through the first layer.

Specifically, the LDPC decoder 1217-1 may perform LDPC decoding usingthe values output from the bit deinterleaver 1216 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100. Thatis, the LDPC decoder 1217-1 may perform the LDPC decoding using thevalues output from the bit deinterleaver 1216 based on the parity checkmatrix used when the LDPC encoder (not shown) of the first encoder 111performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the first layer signal.

In addition, the BCH decoder 1217-2 may perform BCH decoding on the LDPCinformation word bits restored by the LDPC decoder 1217-1 using a methodcorresponding to the BCH encoding performed by the BCH encoder (notshown) of the first encoder 111 of the transmitting apparatus 100, tothereby restore the information word bits transmitted through the firstlayer.

Meanwhile, in the case in which the second layer signal is to berestored, the LDPC decoder 1217-1 and the BCH decoder 1217-2 may restoreinformation word bits transmitted through the second layer.

Specifically, the LDPC decoder 1217-1 may perform the LDPC decodingusing the values output from the bit deinterleaver 1216 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the second encoder 121 of the transmitting apparatus 100. Thatis, the LDPC decoder 1217-1 may perform the LDPC decoding using thevalues output from the bit deinterleaver 1216 based on the parity checkmatrix used when the LDPC encoder (not shown) of the second encoder 121performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the second layer signal.

In addition, the BCH decoder 1217-2 may perform BCH decoding on the LDPCinformation word bits restored by the LDPC decoder 1217-1 using a methodcorresponding to the BCH encoding performed by the BCH encoder (notshown) of the second encoder 121 of the transmitting apparatus 100, tothereby restore the information word bits transmitted through the secondlayer.

Meanwhile, the LDPC encoder 1218 may encode the LDPC information wordbits decoded by the LDPC decoder 1217-1 to generate the LDPC paritybits.

Specifically, the LDPC encoder 1218 may perform the LDPC encoding on theLDPC information word bits by the LDPC encoding performed by the LDPCencoder (not shown) of the first encoder 111 of the transmittingapparatus 100 to generate the LDPC parity bits, and may output an LDPCcodeword including the LDPC information word bits and the LDPC paritybits to the bit interleaver 1219.

In this case, the LDPC encoder 1218 may encode the LDPC information wordbits based on the parity check matrix used when the LDPC encoder (notshown) of the first encoder 111 performs the LDPC encoding to generatethe LDPC parity bits.

As described above, according to the methods described in FIGS. 11 and12, since the signal corresponding to the first layer is restored byperforming the LDPC encoding on the LDPC information word bits decodedfrom the first layer signal without separately performing the BCHencoding, the time taken to restore the second layer signal may beshortened.

Meanwhile, in FIGS. 9 to 12, the LDPC encoder generates all LDPC paritybits using the LDPC encoding.

However, in FIGS. 9 to 12, the LDPC encoder may generate the LDPC paritybits corresponding only to the columns having the degree of 1 in theparity check matrix, and the bit interleaver may also interleave an LDPCcodeword bits including the LDPC information word bits, the LDPC paritybits generated by the LDPC encoder, and LDPC parity bits correspondingto the columns other than the columns having the degree of 1 in theparity check matrix among the LDPC parity bits restored by the LDPCdecoder.

For example, since the structure of the parity check matrix used at thetime of the LDPC encoding in the transmitting apparatus 100 is equal tothat of FIG. 5, the LDPC encoder generates second LDPC parity bits(p_(0′),p_(1′), . . . , p_(N-K-g-1′)) corresponding to the columnshaving the degree of 1 in the parity check matrix, that is, the secondparity partial matrix.

Here, it is assumed that the LDPC information word bits are (i₀,i₁, . .. , i_(K-1)), and LDPC parity bits other than the second LDPC paritybits in the LDPC parity bits, that is, the first LDPC parity bits are(p₀,p₁, . . . , p_(g-1)).

In this case, the bit interleaver may interleave the LDPC codeword bits(i₀,i₁, . . . , i_(K-1),p₀,p₁, . . . , p_(g-1),p_(0′),p_(1′), . . . ,p_(N-K-g-1′)) including the LDPC information word bits (i₀,i₁, . . . ,i_(K-1)), the first LDPC parity bits (p_(0′),p_(1′), . . . ,p_(N-K-g-1′)) among the LDPC parity bits decoded by the LDPC decoder,and the second LDPC parity bits (p_(0′),p_(1′), . . . , p_(N-K-g-1′))generated by the LDPC encoding, and the constellation mapper maymodulate the interleaved LDPC codeword bits to be mapped to theconstellation points, and may generate the signal corresponding to thefirst layer.

Meanwhile, although the above-mentioned example describes the case inwhich the LDPC parity bits are generated using the LDPC encoding inorder to restore the signal corresponding to the first layer, this ismerely one example. That is, as illustrated in FIGS. 13 to 16, thesignal corresponding to the first layer may also be restored withoutseparately performing the LDPC encoding.

As one example, as illustrated in FIGS. 13 and 14, the signalcorresponding to the first layer may be restored using the LDPC paritybits decoded by the first LDPC decoder without separately performing theLDPC encoding.

FIG. 13 is a block diagram illustrating a detailed configuration of atransmitting apparatus according to an exemplary embodiment.

Referring to FIG. 13, a transmitting apparatus 1000 may include a timedeinterleaver 1311, a first gain controller 1312, a first constellationdemapper 1313, a bit deinterleaver 1314, a first LDPC decoder 1315-1, afirst BCH decoder 1315-2, a bit interleaver 1317, a constellation mapper1318, a second gain controller 1319, a delayer 1320, an adder 1321, athird gain controller 1322, a second constellation demapper 1323, asecond bit deinterleaver 1324, and a second decoder 1325.

Meanwhile, since the time deinterleaver 1311, the first gain controller1312, the first constellation demapper 1313, the bit deinterleaver 1314,the first LDPC decoder 1315-1, the first BCH decoder 1315-2, theconstellation mapper 1318, the second gain controller 1319, the delayer1320, the adder 1321, the third gain controller 1322, the secondconstellation demapper 1323, the second bit deinterleaver 1324, and thesecond decoder 1325 illustrated in FIG. 13 perform the same operationsas the time deinterleaver 1111, the first gain controller 1112, thefirst constellation demapper 1113, the bit deinterleaver 1114, the firstLDPC decoder 1115-1, the first BCH decoder 1115-2, the constellationmapper 1118, the second gain controller 1119, the delayer 1120, theadder 1121, the third gain controller 1122, the second constellationdemapper 1123, the second bit deinterleaver 1124, and the second decoder1125 described in FIG. 11, a detailed description thereof will beomitted.

However, since a signal corresponding to the first layer is restoredwithout separately performing LDPC encoding in FIG. 13, the delayer 1320delays the signal output from the time deinterleaver 1311 as much as atime (Delay T) obtained by summing all times taken to perform a signalprocessing at the first constellation demapper 1313, the first bitdeinterleaver 1314, the first LDPC decoder 1315, the bit interleaver1317, and the constellation mapper 1318.

The bit interleaver 1317 may interleave the bits output from the firstLDPC decoder 1315-1.

Specifically, the bit interleaver 1317 may interleave the LDPC codewordbits including the LDPC information word bits and the LDPC parity bitsdecoded by the first LDPC decoder 1315-1 using the same method as thatperformed by the first bit interleaver 112 of the transmitting apparatus100, and may output the interleaved LDPC codeword bits to theconstellation mapper 1318.

FIG. 14 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 14, a receiving apparatus 1000 may include a buffer1411, a time deinterleaver 1412, a first gain controller 1413, a dataselector 1414, a constellation demapper 1415, a bit deinterleaver 1416,an LDPC decoder 1417-1, a BCH decoder 1417-2, an LDPC encoder 1418, abit interleaver 1419, a constellation mapper 1420, a second gaincontroller 1421, a delayer 1422, an adder 1423, and a third gaincontroller 1424.

Meanwhile, since the buffer 1411, the time deinterleaver 1412, the firstgain controller 1413, the data selector 1414, the constellation demapper1415, the bit deinterleaver 1416, the LDPC decoder 1417-1, the BCHdecoder 1417-2, the constellation mapper 1420, the second gaincontroller 1421, the delayer 1422, the adder 1423, and the third gaincontroller 1424 illustrated in FIG. 14 perform the same operations asthe buffer 1211, the time deinterleaver 1212, the first gain controller1213, the data selector 1214, the constellation demapper 1215, the bitdeinterleaver 1216, the LDPC decoder 1217-1, the BCH decoder 1217-2, theconstellation mapper 1220, the second gain controller 1221, the delayer1222, the adder 1223, and the third gain controller 1224 described inFIG. 12, a detailed description thereof will be omitted.

However, since a signal corresponding to the first layer is restoredusing the decoded bits without separately performing the LDPC encodingin FIG. 14, the delayer 1422 delays the signal output from the timedeinterleaver 1412 as much as a time (Delay T) obtained by summing alltimes taken to perform a signal processing at the constellation demapper1415, the bit deinterleaver 1416, the LDPC decoder 1417-1, the bitinterleaver 1419, and the constellation mapper 1420.

The bit interleaver 1419 may interleave the bits output from the firstLDPC decoder 1315-1.

Specifically, the bit interleaver 1419 may interleave the LDPC codewordbits including the LDPC information word bits and the LDPC parity bitsdecoded by the first LDPC decoder 1417-1 using the same method as thatperformed by the first bit interleaver 112 of the transmitting apparatus100, and may output the interleaved LDPC codeword bits to theconstellation mapper 1420.

As described above, according to the methods described in FIGS. 13 and14, since the signal corresponding to the first layer is restored usingthe LDPC information word bits and the LDPC parity bits decoded from thefirst layer signal without separately performing the LDPC encoding, thetime taken to restore the second layer signal may be shortened.

As another example, as illustrated in FIGS. 15 and 16, the signalcorresponding to the first layer may be restored using the valuesdemapped by the constellation demapper without separately performing theLDPC encoding.

FIG. 15 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 15, a receiving apparatus 1000 may include a timedeinterleaver 1511, a first gain controller 1512, a first constellationdemapper 1513, a bit deinterleaver 1514, a first decoder 1515, aconstellation mapper 1518, a second gain controller 1519, a delayer1520, an adder 1521, a third gain controller 1522, a secondconstellation demapper 1523, a second bit deinterleaver 1524, and asecond decoder 1525.

Meanwhile, since the time deinterleaver 1511, the first gain controller1512, the first constellation demapper 1513, the bit deinterleaver 1514,the first decoder 1515, the second gain controller 1519, the delayer1520, the adder 1521, the third gain controller 1522, the secondconstellation demapper 1523, the second bit deinterleaver 1524, and thesecond decoder 1525 illustrated in FIG. 15 perform the same operationsas the time deinterleaver 911, the first gain controller 912, the firstconstellation demapper 913, the bit deinterleaver 914, the first decoder915, the second gain controller 919, the delayer 920, the adder 921, thethird gain controller 922, the second constellation demapper 923, thesecond bit deinterleaver 924, and the second decoder 925 described inFIG. 9, a detailed description thereof will be omitted.

However, since a signal corresponding to the first layer is restoredusing the demapped values without separately performing the LDPCencoding in FIG. 11, the delayer 1520 delays the signal output from thetime deinterleaver 1511 as much as a time (Delay T) obtained by summingall times taken to perform a signal processing at the firstconstellation demapper 1513, and the constellation mapper 1518.

The constellation mapper 1518 may modulate the values output from thefirst constellation demapper 1513 to be mapped to constellation points.

Specifically, the constellation mapper 1518 may modulate the valuesoutput from the first constellation mapper 1513 using the same method asthat performed by the first constellation mapper 113 of the transmittingapparatus 100 to be mapped to the constellation points, and may outputthe signal corresponding to the constellation points to the second gaincontroller 1519.

FIG. 16 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 16, a receiving apparatus 1000 may include a buffer1611, a time deinterleaver 1612, a first gain controller 1613, a dataselector 1614, a constellation demapper 1615, a bit deinterleaver 1616,a decoder 1617, a constellation mapper 1620, a second gain controller1621, a delayer 1622, an adder 1623, and a third gain controller 1624.

Meanwhile, since the buffer 1611, the time deinterleaver 1612, the firstgain controller 1613, the data selector 1614, the constellation demapper1615, the bit deinterleaver 1616, the decoder 1617, the second gaincontroller 1621, the delayer 1622, the adder 1623, and the third gaincontroller 1624 illustrated in FIG. 16 perform the same operations asthe buffer 1011, the time deinterleaver 1012, the first gain controller1013, the data selector 1014, the constellation demapper 1015, the bitdeinterleaver 1016, the decoder 1017, the encoder 1018, the bitinterleaver 1019, the second gain controller 1021, the delayer 1022, theadder 1023, and the third gain controller 1024 described in FIG. 10, adetailed description thereof will be omitted.

However, since a signal corresponding to the first layer is restoredusing the demapped values without separately performing the LDPCencoding in FIG. 16, the delayer 1622 delays the signal output from thetime deinterleaver 1615 as much as a time (Delay T) obtained by summingall times taken to perform a signal processing at the firstconstellation demapper 1620, and the constellation mapper 1612.

The constellation mapper 1620 may modulate the values output from thefirst constellation demapper 1615 to be mapped to constellation points.

Specifically, the constellation mapper 1620 may modulate the valuesoutput from the first constellation mapper 1615 using the same method asthat performed by the first constellation mapper 113 of the transmittingapparatus 100 to be mapped to the constellation points, and may outputthe signal corresponding to the constellation points to the second gaincontroller 1621.

As described above, according to the methods described in FIGS. 15 and16, since the signal corresponding to the first layer is restored usingthe values demodulated from the first layer signal without separatelyperforming the LDPC encoding, the time taken to restore the second layersignal may be shortened.

Meanwhile, N_(o,UL) illustrated in FIGS. 9 to 16 denotes variance ofnoise included in the LDM signal when the bits transmitted through thefirst layer signal are restored from the LDM signal, and N_(o,LL)denotes variance of noise included in the signal obtained by removingthe first layer signal from the LDM signal when the bits transmittedthrough the second layer signal are restored from the LDM signal.Meanwhile, Es denotes power of the output signal of the constellationmapper before being scaled with P_(UL) and P_(LL), and N_(O) denoteseffective noise variance required when a current signal is detected fromthe constellation demapper.

Accordingly, the constellation demapper may remove the noise from thesignal by assuming the values except for the signal and channelcomponents as the noise variance, and may generate values correspondingto the bits transmitted through each of the layers.

Meanwhile, in the examples described above, the first layer signal issearched from the LDM signal to be demodulated, and the signal obtainedby removing the signal corresponding to the first layer from the LDMsignal, that is, the second layer signal is demodulated.

However, according to an exemplary embodiment, the first layer signaland the second layer signal may be demodulated at a time by searchingfor both the first layer signal and the second layer signal from the LDMsignal, and in the case in which the first layer signal and the secondlayer signal are demodulated at a time using the above-mentionedfull-search, a method for restoring the information word bitstransmitted through each of the layers will be described in more detail.

FIG. 17 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 17, a receiving apparatus 1000 may include a timedeinterleaver 1711, a joint constellation demapper 1712, a data selector1713, a bit deinterleaver 1714, a decoder 1715, and a buffer 1716.

The time deinterleaver 1711 deinterleaves cells demapped from a symbolof an OFDM frame.

Specifically, the time deinterleaver 1711, which is a configurationcorresponding to the time interleaver 160 of the transmitting apparatus100, may inversely perform the operation performed by the timeinterleaver 160. That is, the time deinterleaver 1711 may deinterleavethe cells demapped from sub-carriers of the symbol, and may output thedeinterleaved cells to the joint constellation demapper 1712 and thebuffer 1713.

The joint constellation demapper 1712 may demodulate the signal outputfrom the time deinterleaver 1711, to thereby generate valuescorresponding to bits transmitted through the first and second layers.

Specifically, the joint constellation demapper 1712 may perform afull-search for the signal output the time deinterleaver 1711 based onthe modulation scheme performed by the first constellation mapper 113and the second constellation mapper 123 of the transmitting apparatus100 to search for constellation points corresponding to the first layersignal and the second layer signal, and may demodulate the constellationpoints to generate the values corresponding to bits transmitted throughthe first layer and the second layer.

Here, the value corresponding to the bits transmitted from thetransmitting apparatus 100 is typically a value calculated based onpossibility that the received bit is 0 and possibility that the receivedbit is 1, wherein each of the probabilities itself may be used as thevalue corresponding to each of the bits, and as another example, thevalue corresponding to the bits transmitted from the transmittingapparatus 100 may also be an LR or LLR value.

Specifically, the LR value means a ratio of the possibility that the bittransmitted from the transmitting apparatus 100 is 0 and the possibilitythat the bit transmitted from the transmitting apparatus 100 is 1, andthe LLR value may be represented by a value obtained by taking Log tothe ratio of the possibility that the bit transmitted from thetransmitting apparatus 100 is 0 and the possibility that the bittransmitted from the transmitting apparatus 100 is 1.

Meanwhile, although the above-mentioned example describes the case inwhich the LR value or the LLR value is used, this is one example, andthe received signal itself may also be used.

In addition, the joint constellation demapper 1712 may output the valuescorresponding to the bits transmitted through the first layer to thedata selector 1713, and may output the values corresponding to the bitstransmitted through the second layer to the buffer 1716.

The data selector 1713 may receive the signals output from the jointconstellation demapper 1712 and the buffer 1716, and may select one ofthe signals to be output.

Specifically, in the case in which the first layer signal is decoded,the data selector 1713 may output the signal received from the jointconstellation demapper 1712 to the bit deinterleaver 1714.

The bit deinterleaver 1714 may deinterleave the signal output from thedata selector 1713.

Specifically, in the case in which the first layer signal is decoded,the bit deinterleaver 1714 may inversely perform the operation performedby the first bit interleaver 112 of the transmitting apparatus 100, tothereby deinterleave the value corresponding to the bits and to outputthe deinterleaved values to the decoder 1715.

The decoder 1715 may restore information word bits transmitted throughthe first layer using the values output from the bit deinterleaver 1714.

To this end, the decoder 1715 may include an LDPC decoder (not shown)and a BCH decoder (not shown).

Specifically, the LDPC decoder (not shown) may perform LDPC decodingusing the values output from the bit deinterleaver 1714 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100. Thatis, the LDPC decoder (not shown) may perform the LDPC decoding using thevalues output from the bit deinterleaver 1714 based on the parity checkmatrix used when the LDPC encoder (not shown) of the first encoder 111performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the first layer signal.

In addition, the BCH decoder (not shown) may perform BCH decoding on theLDPC information word bits restored by the LDPC decoder (not shown)using a method corresponding to the BCH encoding performed by the BCHencoder (not shown) of the first encoder 111 of the transmittingapparatus 100, to thereby restore the information word bits transmittedthrough the first layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

The buffer 1716 may store the signal output from the joint constellationdemapper 1712, and may output the stored signal to the data selector1713 when the decoding of the first layer signal is completed.

Specifically, the buffer 1716 may receive and store the valuescorresponding to the second layer signal generated based on the cellsdemapped from the k-th sub-carrier of the symbol of the OFDM frame fromthe joint constellation demapper 1712, and may output the valuescorresponding to the second layer signal generated based on the cellsdemapped from the k-th sub-carrier to the data selector 1713 when thedecoding for the first layer signal transmitted through the k-thsub-carrier is completed and the restoration for the information wordbits transmitted through the first layer is completed.

The data selector 1713 may receive the signals output from the jointconstellation demapper 1712 and the buffer 1716, and may select one ofthe signals to be output.

Specifically, in the case in which the second layer signal is to bedecoded, the data selector 1713 may output the signal received from thejoint constellation demapper 1716 to the bit deinterleaver 1714.

The bit deinterleaver 1714 may deinterleave the signal output from thedata selector 1713.

Specifically, in the case in which the second layer signal is to bedecoded, the bit deinterleaver 1714 may inversely perform the operationperformed by the second bit interleaver 122 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the decoder 1715.

The decoder 1715 may restore information word bits transmitted throughthe second layer using the values output from the bit deinterleaver1714.

To this end, the decoder 1715 may include an LDPC decoder (not shown)and a BCH decoder (not shown).

Specifically, the LDPC decoder (not shown) may perform LDPC decodingusing the values output from the bit deinterleaver 1714 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the second encoder 121 of the transmitting apparatus 100. Thatis, the LDPC decoder (not shown) may perform the LDPC decoding using thevalues output from the bit deinterleaver 1714 based on the parity checkmatrix used when the LDPC encoder (not shown) of the second encoder 121performs the LDPC encoding, to thereby restored LDPC information wordbits and LDPC parity bits from the second layer signal.

In addition, the BCH decoder (not shown) may perform BCH decoding on theLDPC information word bits restored by the LDPC decoder (not shown)using a method corresponding to the BCH encoding performed by the BCHencoder (not shown) of the second encoder 121 of the transmittingapparatus 100, to thereby restore the information word bits transmittedthrough the second layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

FIG. 18 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 18, a receiving apparatus 1000 may include a timedeinterleaver 1811, a joint constellation demapper 1812, a first bitdeinterleaver 1813, a first decoder 1814, a second bit deinterleaver1815, and a second decoder 1816.

The time deinterleaver 1811 deinterleaves cells demapped from a symbolof an OFDM frame.

Specifically, the time deinterleaver 1811, which is a configurationcorresponding to the time interleaver 160 of the transmitting apparatus100, may inversely perform the operation performed by the timeinterleaver 160. That is, the time deinterleaver 1811 may deinterleavethe cells demapped from sub-carriers of the symbol, and may output thedeinterleaved cells to the joint constellation demapper 1812.

The joint constellation demapper 1812 may demodulate the signal outputfrom the time deinterleaver 1811, to thereby generate valuescorresponding to the bits transmitted through the first and secondlayers.

Specifically, the joint constellation demapper 1812 may perform afull-search for a signal output the time deinterleaver 1811 based on themodulation scheme performed by the first constellation mapper 113 andthe second constellation mapper 123 of the transmitting apparatus 100 tosearch for constellation points corresponding to the first layer signaland the second layer signal, and may demodulate the constellation pointsto generate the values corresponding to bits transmitted through thefirst layer and the second layer.

In addition, the joint constellation demapper 1812 may output the valuescorresponding to the bits transmitted through the first layer to thefirst bit deinterleaver 1813, and may output the values corresponding tothe bits transmitted through the second layer to the second bitdeinterleaver 1815.

The first bit deinterleaver 1813 may deinterleave the signal output fromthe joint constellation demapper 1812.

Specifically, the first bit deinterleaver 1813 may inversely perform theoperation performed by the first bit interleaver 112 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the first decoder 1814.

The first decoder 1814 may restore information word bits transmittedthrough the first layer using the values output from the first bitdeinterleaver 1813.

To this end, the first decoder 1814 may include a first LDPC decoder(not shown) and a first BCH decoder (not shown).

Specifically, the first LDPC decoder (not shown) may perform LDPCdecoding using the values output from the first bit deinterleaver 1813using a method corresponding to the LDPC encoding performed by the LDPCencoder (not shown) of the first encoder 111 of the transmittingapparatus 100. That is, the first LDPC decoder (not shown) may performthe LDPC decoding using the values output from the first bitdeinterleaver 1813 based on the parity check matrix used when the LDPCencoder (not shown) of the first encoder 111 performs the LDPC encoding,to thereby restore LDPC information word bits and LDPC parity bits fromthe first layer signal.

In addition, the first BCH decoder (not shown) may perform BCH decodingon the LDPC information word bits decoded by the first LDPC decoder (notshown) using a method corresponding to the BCH encoding performed by theBCH encoder (not shown) of the first encoder 111 of the transmittingapparatus 100, to thereby restore the information word bits transmittedthrough the first layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

The second bit deinterleaver 1815 may deinterleave the signal outputfrom the joint constellation demapper 1812.

Specifically, the second bit deinterleaver 1815 may inversely performthe operation performed by the second bit interleaver 122 of thetransmitting apparatus 100, to thereby deinterleave the valuecorresponding to the bits and to output the deinterleaved values to thesecond decoder 1816.

The second decoder 1816 may restore information word bits transmittedthrough the second layer using the values output from the second bitdeinterleaver 1815.

To this end, the second decoder 1816 may include a second LDPC decoder(not shown) and a second BCH decoder (not shown).

Specifically, the second LDPC decoder (not shown) may perform LDPCdecoding using the values output from the second bit deinterleaver 1815using a method corresponding to the LDPC encoding performed by the LDPCencoder (not shown) of the second encoder 121 of the transmittingapparatus 100. That is, the LDPC decoder (not shown) may perform theLDPC decoding using the values output from the second bit deinterleaver1815 based on the parity check matrix used when the LDPC encoder (notshown) of the second encoder 121 performs the LDPC encoding, to therebyrestore LDPC information word bits and LDPC parity bits from the secondlayer signal.

In addition, the second BCH decoder (not shown) may perform BCH decodingon the LDPC information word bits decoded by the second LDPC decoder(not shown) using a method corresponding to the BCH encoding performedby the BCH encoder (not shown) of the second encoder 121 of thetransmitting apparatus 100, to thereby restore the information word bitstransmitted through the second layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

FIG. 19 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 19, a receiving apparatus 1000 may include a timedeinterleaver 1911, a constellation demapper 1912, a data selector 1913,a bit deinterleaver 1914, a decoder 1915, a buffer 1916, and a jointconstellation demapper 1917.

The time deinterleaver 1911 deinterleaves cells demapped from a symbolof an OFDM frame.

Specifically, the time deinterleaver 1911, which is a configurationcorresponding to the time interleaver 160 of the transmitting apparatus100, may inversely perform the operation performed by the timeinterleaver 160. That is, the time deinterleaver 1911 may deinterleavethe cells demapped from sub-carriers of the symbol, and may output thedeinterleaved cells to the constellation demapper 1912 and the buffer1913.

The constellation demapper 1912 may demodulate the signal output fromthe time deinterleaver 1911, to thereby generate values corresponding tothe bits transmitted through the first layer.

Specifically, the constellation demapper 1912 may demodulate the signaloutput from the time deinterleaver 1911 based on the modulation schemeperformed by the first constellation mapper 113 of the transmittingapparatus 100 to generate the values corresponding to the bitstransmitted through the first layer, and may output the values to thedata selector 1913.

The data selector 1913 may receive the signals output from theconstellation demapper 1912 and the joint constellation demapper 1917,and may select one of the signals to be output.

Specifically, in the case in which the first layer signal is to bedecoded, the data selector 1913 may output the signal received from theconstellation demapper 1912 to the bit deinterleaver 1914.

The bit deinterleaver 1914 may deinterleave the signal output from thedata selector 1913.

Specifically, in the case in which the first layer signal is to bedecoded, the bit deinterleaver 1914 may inversely perform the operationperformed by the first bit interleaver 112 of the transmitting apparatus100, to thereby deinterleave the value corresponding to the bits and tooutput the deinterleaved values to the decoder 1915.

The decoder 1915 may restore information word bits transmitted throughthe first layer using the values output from the bit deinterleaver 1914.

To this end, the decoder 1915 may include an LDPC decoder (not shown)and a BCH decoder (not shown).

Specifically, the LDPC decoder (not shown) may perform LDPC decodingusing the values output from the bit deinterleaver 1914 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the first encoder 111 of the transmitting apparatus 100. Thatis, the LDPC decoder (not shown) may perform the LDPC decoding using thevalues output from the bit deinterleaver 1914 based on the parity checkmatrix used when the LDPC encoder (not shown) of the first encoder 111performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the first layer signal.

In addition, the BCH decoder (not shown) may perform BCH decoding on theLDPC information word bits decoded by the LDPC decoder (not shown) usinga method corresponding to the BCH encoding performed by the BCH encoder(not shown) of the first encoder 111 of the transmitting apparatus 100,to thereby restore the information word bits transmitted through thefirst layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

The buffer 1916 may store the signal output from the time deinterleaver1911, and may output the stored signal to the joint constellationdemapper 1917 when the decoding for the first layer signal is completed.

Specifically, the buffer 1916 may receive and store the cells demappedfrom the k-th sub-carrier of the symbol of the OFDM frame from the timedeinterleaver 1911, and may output the cells demapped from the k-thsub-carrier to the data selector 1913 when the decoding for the firstlayer signal transmitted through the k-th sub-carrier is completed andthe restoration for the information word bits transmitted through thefirst layer is completed.

The joint constellation demapper 1917 may demodulate the signal outputfrom the buffer 1916, to thereby generate values corresponding to thebits transmitted through the second layer.

Specifically, the joint constellation demapper 1917 may perform afull-search for the signal output the buffer 1916 based on themodulation scheme performed by the first constellation mapper 113 andthe second constellation mapper 123 of the transmitting apparatus 100 tosearch for constellation points corresponding to the first layer signaland the second layer signal, and may demodulate the constellation pointscorresponding to the second layer signal to generate the valuescorresponding to the bits transmitted through the second layer.

In addition, the joint constellation demapper 1917 may output the valuescorresponding to the bits transmitted through the second layer to thedata selector 1913.

The data selector 1913 may receive the signals output from the jointconstellation demapper 1912 and the buffer 1917, and may select one ofthe signals to be output.

Specifically, in the case in which the second layer signal is to bedecoded, the data selector 1913 may output the signal received from thejoint constellation demapper 1917 to the bit deinterleaver 1914.

The bit deinterleaver 1914 may deinterleave the signal output from thedata selector 1913.

Specifically, in the case in which the second layer signal is to bedecoded, the bit deinterleaver 1914 may inversely perform the operationperformed by the second bit interleaver 122 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the decoder 1915.

The decoder 1915 may restore information word bits transmitted throughthe second layer using the values output from the bit deinterleaver1914.

To this end, the decoder 1915 may include an LDPC decoder (not shown)and a BCH decoder (not shown).

Specifically, the LDPC decoder (not shown) may perform LDPC decodingusing the values output from the bit deinterleaver 1914 using a methodcorresponding to the LDPC encoding performed by the LDPC encoder (notshown) of the second encoder 121 of the transmitting apparatus 100. Thatis, the LDPC decoder (not shown) may perform the LDPC decoding using thevalues output from the bit deinterleaver 1914 based on the parity checkmatrix used when the LDPC encoder (not shown) of the second encoder 121performs the LDPC encoding, to thereby restore LDPC information wordbits and LDPC parity bits from the second layer signal.

In addition, the BCH decoder (not shown) may perform BCH decoding on theLDPC information word bits decoded by the LDPC decoder (not shown) usinga method corresponding to the BCH encoding performed by the BCH encoder(not shown) of the second encoder 121 of the transmitting apparatus 100,to thereby restore the information word bits transmitted through thesecond layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

FIG. 20 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 20, a receiving apparatus 1000 may include a timedeinterleaver 2011, a constellation demapper 2012, a first bitdeinterleaver 2013, a first decoder 2014, a joint constellation demapper2015, a second bit deinterleaver 2016, and a second decoder 2017.

The time deinterleaver 2011 deinterleaves cells demapped from a symbolof an OFDM frame.

Specifically, the time deinterleaver 2011, which is a configurationcorresponding to the time interleaver 160 of the transmitting apparatus100, may inversely perform the operation performed by the timeinterleaver 160. That is, the time deinterleaver 2011 may deinterleavethe cells demapped from the sub-carrier of the symbol, and may outputthe deinterleaved cells to the constellation demapper 2012 and the jointconstellation demapper 2015.

The constellation demapper 2012 may demodulate the signal output fromthe time deinterleaver 2011, to thereby generate values corresponding tothe bits transmitted through the first layer.

Specifically, the constellation demapper 2012 may demodulate the signaloutput from the time deinterleaver 2011 based on the modulation schemeperformed by the first constellation mapper 113 of the transmittingapparatus 100 to generate the values corresponding to the bitstransmitted through the first layer, and may output the values to thefirst bit deinterleaver 2013.

The first bit deinterleaver 2013 may deinterleave the signal output fromthe constellation demapper 2012.

Specifically, the first bit deinterleaver 2013 may inversely perform theoperation performed by the first bit interleaver 112 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the first decoder 2014.

The first decoder 2014 may restore information word bits transmittedthrough the first layer using the values output from the first bitdeinterleaver 2013.

To this end, the first decoder 2014 may include a first LDPC decoder(not shown) and a first BCH decoder (not shown).

Specifically, the first LDPC decoder (not shown) may perform LDPCdecoding using the values output from the first bit deinterleaver 2013using a method corresponding to the LDPC encoding performed by the LDPCencoder (not shown) of the first encoder 111 of the transmittingapparatus 100. That is, the first LDPC decoder (not shown) may performthe LDPC decoding using the values output from the first bitdeinterleaver 2013 based on the parity check matrix used when the LDPCencoder (not shown) of the first encoder 111 performs the LDPC encoding,to thereby restore LDPC information word bits and LDPC parity bits fromthe first layer signal.

In addition, the first BCH decoder (not shown) may perform BCH decodingon the LDPC information word bits decoded by the first LDPC decoder (notshown) using a method corresponding to the BCH encoding performed by theBCH encoder (not shown) of the first encoder 111 of the transmittingapparatus 100, to thereby restore the information word bits transmittedthrough the first layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

The joint constellation demapper 2015 may demodulate the signal outputfrom the time deinterleaver 2011, to thereby generate valuescorresponding to the bits transmitted through the second layer.

Specifically, the joint constellation demapper 2015 may perform afull-search for the signal output the time deinterleaver 2011 based onthe modulation scheme performed by the first constellation mapper 113and the second constellation mapper 123 of the transmitting apparatus100 to search for constellation points corresponding to the first layersignal and the second layer signal, and may demodulate the constellationpoints corresponding to the second layer signal to generate the valuescorresponding to the bits transmitted through the second layer.

In addition, the joint constellation demapper 2015 may output the valuescorresponding to the bits transmitted through the layer to the secondbit deinterleaver 2016.

The second bit deinterleaver 2016 may deinterleave the signal outputfrom the joint constellation demapper 2015.

Specifically, the second bit deinterleaver 2016 may inversely performthe operation performed by the second bit interleaver 122 of thetransmitting apparatus 100, to thereby deinterleave the valuecorresponding to the bits and to output the deinterleaved values to thesecond decoder 2017.

The second decoder 2017 may restore information word bits transmittedthrough the second layer using the values output from the second bitdeinterleaver 2016.

To this end, the second decoder 2017 may include a second LDPC decoder(not shown) and a second BCH decoder (not shown).

Specifically, the second LDPC decoder (not shown) may perform LDPCdecoding using the values output from the second bit deinterleaver 2016using a method corresponding to the LDPC encoding performed by the LDPCencoder (not shown) of the second encoder 121 of the transmittingapparatus 100. That is, the second LDPC decoder (not shown) may performthe LDPC decoding using the values output from the second bitdeinterleaver 2016 based on the parity check matrix used when the LDPCencoder (not shown) of the second encoder 121 performs the LDPCencoding, to thereby restore LDPC information word bits and LDPC paritybits from the second layer signal.

In addition, the second BCH decoder (not shown) may perform the BCHdecoding for the LDPC information word bits decoded by the second LDPCdecoder (not shown) using a method corresponding to the BCH encodingperformed by the BCH encoder (not shown) of the second encoder 121 ofthe transmitting apparatus 100, to thereby restore the information wordbits transmitted through the second layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

FIG. 21 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 21, a receiving apparatus 1000 may include a timedeinterleaver 2111, a constellation demapper 2112, a data selector 2113,a bit deinterleaver 2114, an LDPC decoder 2115, a BCH decoder 2116, anLLR coupler 2117, a bit interleaver 2118, a delayer 2119, and a jointconstellation demapper 2120.

The time deinterleaver 2111 deinterleaves cells demapped from a symbolof an OFDM frame.

Specifically, the time deinterleaver 2111, which is a configurationcorresponding to the time interleaver 160 of the transmitting apparatus100, may inversely perform the operation performed by the timeinterleaver 160. That is, the time deinterleaver 2111 may deinterleavethe cells demapped from sub-carriers of the symbol, and may output thedeinterleaved cells to the constellation demapper 2112 and the delayer2119.

The constellation demapper 2112 may demodulate the signal output fromthe time deinterleaver 2111, to thereby generate values corresponding tothe bits transmitted through the first layer.

Specifically, the constellation demapper 2112 may demodulate the signaloutput from the time deinterleaver 2111 based on the modulation schemeperformed by the first constellation mapper 113 of the transmittingapparatus 100 to generate the values corresponding to the bitstransmitted through the first layer, and may output the values to thedata selector 2113.

The data selector 2113 may receive the signals output from theconstellation demapper 2112 and the joint constellation demapper 2120,and may select one of the signals to be output.

Specifically, in the case in which the first layer signal is to bedecoded, the data selector 2113 may output the signal received from theconstellation demapper 2112 to the bit deinterleaver 2114.

The bit deinterleaver 2114 may deinterleave the signal output from thedata selector 2113.

Specifically, in the case in which the first layer signal is to bedecoded, the bit deinterleaver 2114 may inversely perform the operationperformed by the bit interleaver 112 of the transmitting apparatus 100,to thereby deinterleave the value corresponding to the bits and tooutput the deinterleaved values to the LDPC decoder 2115.

The LDPC decoder 2115 may restore information word bits transmittedthrough the first layer using the values output from the bitdeinterleaver 2114.

Specifically, in the case in which the first layer signal is decoded,the LDPC decoder 2115 may perform LDPC decoding using the values outputfrom the bit deinterleaver 2114 using a method corresponding to the LDPCencoding performed by the LDPC encoder (not shown) of the first encoder111 of the transmitting apparatus 100. That is, the LDPC decoder 2115may perform the LDPC decoding using the values output from the bitdeinterleaver 2114 based on the parity check matrix used when the LDPCencoder (not shown) of the first encoder 111 performs the LDPC encoding,to thereby restore LDPC information word bits and LDPC parity bits fromthe first layer signal.

In addition, in the case in which the first layer signal is decoded, theBCH decoder 2116 may perform BCH decoding on the LDPC information wordbits decoded by the LDPC decoder 2115 using a method corresponding tothe BCH encoding performed by the BCH encoder (not shown) of the firstencoder 111 of the transmitting apparatus 100, to thereby restore theinformation word bits transmitted through the first layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

The LLR coupler 2117 may sum LLR values, and may output the summed LLRvalues to the bit interleaver 2118.

Specifically, the bit deinterleaver 2114 may deinterleave the valuescorresponding to the bits transmitted through the first layer, that is,the LLR values to output the deinterleaved values to the LLR coupler2117. In addition, the LDPC decoder 2115 may update the LLR valuesreceived from the bit deinterleaver 2114 using a message passingoperation, and may decide the bit value as 0 or 1 based on the updatedLLR values to decode the LDPC information word bits and the LDPC paritybits from the first layer signal, wherein the updated LLR values may beoutput to the LLR coupler 2117.

Accordingly, the LLR coupler 2117 may couple the LLR values receivedfrom the bit deinterleaver 2114 and the LLR values received from theLDPC decoder 2115, and may output the coupled LLR values to the bitinterleaver 2118.

Specifically, the LLR coupler 2117 may subtract the LLR values receivedfrom the bit deinterleaver 2114 from the LLR values received from theLDPC decoder 2115, and may then output the value (i.e., extrinsicLLR=LLR of LDPC decoder output−LLR of LDPC decoder input) to the bitinterleaver 2118.

The bit interleaver 2118 may interleave the values output from the LLRcoupler 2117.

Specifically, the bit interleaver 2118 may interleave the values outputfrom the LLR coupler 2117 with the same system as that performed by thefirst bit interleaver 112 of the transmitting apparatus 100, and mayoutput the interleaved values to the joint constellation mapper 2120.

The delayer 2119 may delay the signal output from the time deinterleaver2111 to output the delayed signal.

Specifically, the delayer 2119 may delay the signal output from the timedeinterleaver 2112 as much as a time (Delay T) obtained by summing alltimes taken to perform a signal processing at the constellation demapper2112, the data selector 2113, the bit deinterleaver 2114, the LDPCdecoder 2115, the LLR coupler 2117, and the bit interleaver 2118 tooutput the delayed signal to the joint constellation demapper 2120.

The joint constellation demapper 2120 may demodulate the signal outputfrom the delayer 2119, to thereby generate values corresponding to thebits transmitted through the second layer.

Specifically, the joint constellation demapper 2120 may perform afull-search for the signal output the delayer 2119 based on themodulation scheme performed by the first constellation mapper 113 andthe second constellation mapper 123 of the transmitting apparatus 100 tosearch for constellation points corresponding to the first layer signaland the second layer signal, and may demodulate the constellation pointscorresponding to the second layer signal to generate the valuescorresponding to the bits transmitted through the second layer.

In this case, the joint constellation demapper 2120 may utilize the LLRvalues for the first layer signal output from the LLR coupler 2117 atthe time of the full-searching as a priori LLR value to thereby searchfor the constellation points corresponding to the first layer signal andthe second layer signal. As such, in a joint detection process in whichthe constellation points corresponding to the first layer signal and thesecond layer signal are searched through the full-search to calculatethe LLR values corresponding to the constellation points, the jointconstellation demapper 2120 may utilize the LLR values for the firstlayer signal as a priori probability value.

In addition, the joint constellation demapper 2120 may output the valuescorresponding to the bits transmitted through the second layer to thedata selector 2113.

The data selector 2113 may receive the signals output from theconstellation demapper 2112 and the joint constellation demapper 2120,and may select one of the signals to be output.

Specifically, in the case in which the second layer signal is to bedecoded, the data selector 2113 may output the signal received from thejoint constellation demapper 2120 to the bit deinterleaver 2114.

The bit deinterleaver 2114 may deinterleave the signal output from thedata selector 2113.

Specifically, in the case in which the second layer signal is to bedecoded, the bit deinterleaver 2114 may inversely perform the operationperformed by the second bit interleaver 122 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the deinterleaved values to the LDPC decoder 2115.

The LDPC decoder 2115 may restore information word bits transmittedthrough the second layer using the values output from the bitdeinterleaver 2114.

Specifically, in the case in which the second layer signal is decoded,the LDPC decoder 2115 may perform LDPC decoding using the values outputfrom the bit deinterleaver 2114 using a method corresponding to the LDPCencoding performed by the LDPC encoder (not shown) of the second encoder121 of the transmitting apparatus 100. That is, the LDPC decoder 2115may perform the LDPC decoding using the values output from the bitdeinterleaver 2114 based on the parity check matrix used when the LDPCencoder (not shown) of the second encoder 121 performs the LDPCencoding, to thereby restore LDPC information word bits and LDPC paritybits from the second layer signal.

In addition, in the case in which the second layer signal is decoded,the BCH decoder 2116 may perform BCH decoding on the LDPC informationword bits decoded by the LDPC decoder 2115 using a method correspondingto the BCH encoding performed by the BCH encoder (not shown) of thesecond encoder 121 of the transmitting apparatus 100, to thereby restorethe information word bits transmitted through the second layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

FIG. 22 is a block diagram illustrating a detailed configuration of areceiving apparatus according to an exemplary embodiment.

Referring to FIG. 22, the receiving apparatus 1000 may include a timedeinterleaver 2211, a constellation demapper 2212, a first bitdeinterleaver 2213, a first LDPC decoder 2214, a first BCH decoder 2215,an LLR coupler 2216, a bit interleaver 2217, a delayer 2218, a jointconstellation demapper 2219, a second bit deinterleaver 2220, a secondLDPC decoder 2221, and a second BCH decoder 2222.

The time deinterleaver 2211 deinterleaves cells demapped from a symbolof an OFDM frame.

Specifically, the time deinterleaver 2211, which is a configurationcorresponding to the time interleaver 160 of the transmitting apparatus100, may inversely perform the operation performed by the timeinterleaver 160. That is, the time deinterleaver 2211 may deinterleavethe cells demapped from sub-carriers of the symbol, and may output thedeinterleaved cells to the constellation demapper 2212 and the delayer2218.

The constellation demapper 2212 may demodulate the signal output fromthe time deinterleaver 2211, to thereby generate values corresponding tothe bits transmitted through the first layer.

Specifically, the constellation demapper 2212 may demodulate the signaloutput from the time deinterleaver 2111 based on the modulation schemeperformed by the first constellation mapper 113 of the transmittingapparatus 100 to generate the values corresponding to the bitstransmitted through the first layer, and may output the values to thefirst bit deinterleaver 2213.

The first bit deinterleaver 2213 may deinterleave the signal output fromthe constellation demapper 2212.

Specifically, the first bit deinterleaver 2213 may inversely perform theoperation performed by the first bit interleaver 112 of the transmittingapparatus 100, to thereby deinterleave the value corresponding to thebits and to output the first LDPC decoder 2214.

The first LDPC decoder 2214 may restore information word bitstransmitted through the first layer using the values output from thefirst bit deinterleaver 2213.

Specifically, the first LDPC decoder 2214 may perform LDPC decodingusing the values output from the first bit deinterleaver 2213 using amethod corresponding to the LDPC encoding performed by the LDPC encoder(not shown) of the first encoder 111 of the transmitting apparatus 100.That is, the first LDPC decoder 2214 may perform the LDPC decoding usingthe values output from the first bit deinterleaver 2213 based on theparity check matrix used when the LDPC encoder (not shown) of the firstencoder 111 performs the LDPC encoding, to thereby restore LDPCinformation word bits and LDPC parity bits from the first layer signal.

In addition, the first BCH decoder 2215 may perform BCH decoding on theLDPC information word bits decoded by the first LDPC decoder (not shown)using a method corresponding to the BCH encoding performed by the BCHencoder (not shown) of the first encoder 111 of the transmittingapparatus 100, to thereby restore the information word bits transmittedthrough the first layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the first layersignal.

The LLR coupler 2216 may sum LLR values, and may output the summed LLRvalues to the bit interleaver 2217.

Specifically, the first bit deinterleaver 2213 may deinterleave thevalues corresponding to the bits transmitted through the first layer,that is, the LLR values to output the deinterleaved values to the LLRcoupler 2216. In addition, the LDPC decoder 2214 may update the LLRvalues received from the first bit deinterleaver 2213 using a messagepassing operation, and may decide the bit value as 0 or 1 based on theupdated LLR values to decode the LDPC information word bits and the LDPCparity bits from the first layer signal, wherein the updated LLR valuesmay be output to the LLR coupler 2216.

Accordingly, the LLR coupler 2216 may couple the LLR values receivedfrom the first bit deinterleaver 2213 and the LLR values received fromthe first LDPC decoder 2214, and may output the coupled LLR values tothe bit interleaver 2217.

Specifically, the LLR coupler 2216 may subtract the LLR values receivedfrom the first bit deinterleaver 2213 from the LLR values received fromthe LDPC decoder 2214, and may then output the value (i.e., extrinsicLLR=LLR of LDPC decoder output−LLR of LDPC decoder input) to the bitinterleaver 2217.

The bit interleaver 2217 may interleave the values output from the LLRcoupler 2216.

Specifically, the bit interleaver 2217 may interleave the values outputfrom the LLR coupler 2216 with the same system as that performed by thefirst bit interleaver 112 of the transmitting apparatus 100, and mayoutput the interleaved values to the joint constellation mapper 2219.

The delayer 2218 may delay the signal output from the time deinterleaver2211 to output the delayed signal.

Specifically, the delayer 2218 may delay the signal output from the timedeinterleaver 2211 as much as a time (Delay T) obtained by summing alltimes taken to perform a signal processing at the constellation demapper2212, the first bit deinterleaver 2213, the first LDPC decoder 2214, theLLR coupler 2216, and the bit interleaver 2217 to output the delayedsignal to the joint constellation demapper 2219.

The joint constellation demapper 2219 may demodulate the signal outputfrom the delayer 2218, to thereby generate values corresponding to thebits transmitted through the second layer.

Specifically, the joint constellation demapper 2219 may perform thefull-search for the signal output the delayer 2218 based on themodulation scheme performed by the first constellation mapper 113 andthe second constellation mapper 123 of the transmitting apparatus 100 tosearch for the constellation points corresponding to the first layersignal and the second layer signal, and may demodulate the constellationpoints corresponding to the second layer signal to generate the valuescorresponding to the bits transmitted through the second layer.

In this case, the joint constellation demapper 2219 may utilize the LLRvalues for the first layer signal output from the LLR coupler 2216 atthe time of the full-searching as a priori LLR value to thereby searchfor the constellation points corresponding to the first layer signal andthe second layer signal. As such, in a joint detection process in whichthe constellation points corresponding to the first layer signal and thesecond layer signal are searched through the full-search to calculatethe LLR values corresponding to the constellation points, the jointconstellation demapper 2219 may utilize the LLR values for the firstlayer signal as a priori probability value.

In addition, the joint constellation demapper 2219 may output the valuescorresponding to the bits transmitted through the second layer to thesecond bit deinterleaver 2220.

The second bit deinterleaver 2220 may deinterleave the signal outputfrom the joint constellation demapper 2219.

Specifically, the second bit deinterleaver 2220 may inversely performthe operation performed by the second bit interleaver 122 of thetransmitting apparatus 100, to thereby deinterleave the valuecorresponding to the bits and to output the second LDPC decoder 2221.

The second LDPC decoder 2221 may the information word bits transmittedthrough the second layer using the values output from the second bitdeinterleaver 2220.

Specifically, the second LDPC decoder 2221 may perform LDPC decodingusing the values output from the second bit deinterleaver 2213 using amethod corresponding to the LDPC encoding performed by the LDPC encoder(not shown) of the second encoder 121 of the transmitting apparatus 100.That is, the second LDPC decoder 2221) may perform the LDPC decodingusing the values output from the second bit deinterleaver 2220 based onthe parity check matrix used when the LDPC encoder (not shown) of thesecond encoder 121 performs the LDPC encoding, to thereby restore LDPCinformation word bits and LDPC parity bits from the second layer signal.

In addition, the second BCH decoder 2222 may perform BCH decoding on theLDPC information word bits decoded by the second LDPC decoder (notshown) using a method corresponding to the BCH encoding performed by theBCH encoder (not shown) of the second encoder 121 of the transmittingapparatus 100, to thereby restore the information word bits transmittedthrough the second layer.

Through the above-mentioned operations, the receiving apparatus 1000 mayreceive the information word bits transmitted through the second layersignal.

Meanwhile, although the exemplary embodiments described above describethe case in which the BCH decoding is performed, this assumes that thetransmitting apparatus 100 uses a BCH code as an outer code. Therefore,in the case in which the transmitting apparatus 100 uses a CRC code asthe outer code, the receiving apparatus 1000 may also restore theinformation word bits using a CRC decoder instead of the BCH decoder.

Meanwhile, in the case in which the respective layer signals areprocessed by one FEC block, since the time taken to restore the secondlayer signal may be increased as compared to when the respective layersignals are processed in parallel by two FEC blocks, the number ofiteration times may be adjusted at the time of the LDPC decoding byconsidering the increased time in the case in which the respective layersignals are processed by one FEC block.

Specifically, when the signals transmitted through the respective layersare decoded, it is assumed that the number of iteration times requiredto satisfy performance required by the system is N times. In the case inwhich N iterations are performed whenever the respective layer signalsare decoded by one FEC block, a problem that a processing time isdelayed may occur. Accordingly, according to the present disclosure,when the first layer signal is decoded, N₁ iterations may be performed,and when the second layer signal is decoded, N₂ iterations may beperformed (here, N₁+N₂=N, N₁<N₂).

The reason of adjusting the number of iteration times is because it ispossible to restore the bits transmitted through the first layer signalat low error occurrence possibility even though the iteration isperformed at the relatively small number of times when the first layersignal is decoded, since the second layer signal in the LDM signal maybe operated at a sufficiently high signal to noise ratio (SNR) ascompared to the first layer signal, and the LDPC code applied to thefirst layer may be operated even at a low SNR.

FIG. 23 is a flowchart illustrating a decoding method of a receivingapparatus according to an exemplary embodiment.

First, LDPC information word bits and parity bits are restored bydecoding a signal transmitted through a first layer from an LDM signalusing a parity check matrix (S2310).

Next, the LDPC information word bits are encoded using the parity checkmatrix to generate parity bits corresponding only to preset columns inthe parity check matrix (S2320).

Here, the preset columns may be columns having a degree of 1 in theparity check matrix.

Specifically, the parity check matrix may include a first parity checkmatrix including a first information word partial matrix and a firstparity partial matrix, which is a dual diagonal matrix, and a secondparity check matrix including a second information word partial matrixand a second parity partial matrix which is a unit matrix, and in S2320,the parity bits corresponding only to the columns having the degree of 1in the parity check matrix may be generated.

Meanwhile, a signal obtained by removing a signal corresponding to theLDPC information word bits, the parity bits generated at S2320, and theparity bits restored at S2310 except the parity bits generated at S2320from the LDM signal are decoded to restore bits transmitted through asecond layer (S2330).

Meanwhile, in S2310, the LDPC information word bits and the parity bitsmay be restored by decoding the signal transmitted through the firstlayer using a first LDPC decoder, and the LDPC information word bits maybe decoded using a first BCH decoder to restore information word bitstransmitted through the first layer.

In this case, in S2320, the LDPC information word bits are encoded usingthe LDPC encoder to generate the parity bits corresponding only to thepreset columns in the parity check matrix.

In this case, in S2320, the information word bits are encoded using aBCH encoder to generate BCH parity bits, and the LDPC encoder may encodea BCH codeword including the information word bits and the BCH paritybits to generate the parity bits corresponding only to the presetcolumns in the parity check matrix.

Meanwhile, in S2330, the signal obtained by the removing is decoded torestore LDPC information word bits and parity bits corresponding to asignal transmitted through the second layer may be decoded using a firstLDPC decoder, and the LDPC information word bits corresponding to thesignal transmitted through the second layer may be decoded using a firstBCH decoder to restore information word bits transmitted through thesecond layer.

Alternatively, in S2330, the signal obtained by the removing is decodedto restore the LDPC information word bits and the parity bitscorresponding to the signal transmitted through the second layer may bedecoded using a second LDPC decoder, and the LDPC information word bitscorresponding to the signal transmitted through the second layer may bedecoded using a second BCH decoder to restore the information word bitstransmitted through the second layer.

Meanwhile, a non-transitory computer readable medium having a programstored therein may be provided, wherein the program sequentiallyperforms the decoding method according to the present disclosure.

The non-transitory computer readable medium does not mean a mediumstoring data for a short period such as a register, a cache, a memory,or the like, but means a machine-readable medium semi-permanentlystoring the data. Specifically, various applications or programsdescribed above may be stored and provided in the non-transitorycomputer readable medium such as a compact disc (CD), a digitalversatile disk (DVD), a hard disk, a Blu-ray disk, a universal serialbus (USB), a memory card, a read-only memory (ROM), or the like.

At least one of the components, elements, modules or units representedby a block as illustrated in FIGS. 1, 4, 6 and 9-22 may be embodied asvarious numbers of hardware, software and/or firmware structures thatexecute respective functions described above, according to an exemplaryembodiment. For example, at least one of these components, elements,modules or units may use a direct circuit structure, such as a memory, aprocessor, a logic circuit, a look-up table, etc. that may execute therespective functions through controls of one or more microprocessors orother control apparatuses. Also, at least one of these components,elements, modules or units may be specifically embodied by a module, aprogram, or a part of code, which contains one or more executableinstructions for performing specified logic functions, and executed byone or more microprocessors or other control apparatuses. Also, at leastone of these components, elements, modules or units may further includeor may be implemented by a processor such as a central processing unit(CPU) that performs the respective functions, a microprocessor, or thelike. Two or more of these components, elements, modules or units may becombined into one single component, element, module or unit whichperforms all operations or functions of the combined two or morecomponents, elements, modules or units. Also, at least part of functionsof at least one of these components, elements, modules or units may beperformed by another of these components, elements, modules or units.Further, although a bus is not illustrated in the above block diagrams,communication between the components, elements, modules or units may beperformed through the bus. Functional aspects of the above exemplaryembodiments may be implemented in algorithms that execute on one or moreprocessors. Furthermore, the components, elements, modules or unitsrepresented by a block or processing steps may employ any number ofrelated art techniques for electronics configuration, signal processingand/or control, data processing and the like.

Hereinabove, although the exemplary embodiments have been shown anddescribed, it should be understood that the inventive concept is notlimited to the disclosed embodiments and may be variously changedwithout departing from the spirit and the scope of the inventiveconcept. Therefore, the exemplary embodiments described above should beconstrued as including all the changes, equivalents, and substitutionsincluded in the spirit and scope of the inventive concept.

What is claimed is:
 1. A receiving apparatus receiving and processing alayered division multiplexing (LDM) signal, the receiving apparatuscomprising: a first decoder configured to decode a signal transmittedthrough a first layer from the LDM signal using a parity check matrix togenerate low density parity check (LDPC) information word bits andparity bits; an encoder configured to encode the LDPC information wordbits, generated by decoding the signal transmitted through the firstlayer, using the parity check matrix to generate parity bitscorresponding only to preset columns in the parity check matrix; and asecond decoder configured to decode a signal obtained by removing, fromthe LDM signal, a signal corresponding to the LDPC information word bitsgenerated by decoding the signal transmitted through the first layer,the parity bits generated by the encoder, and the parity bits generatedby the first decoder except the parity bits generated by the encoder,thereby to generate information word bits transmitted through a secondlayer.
 2. The receiving apparatus as claimed in claim 1, wherein thepreset columns are columns having a degree of 1 in the parity checkmatrix.
 3. The receiving apparatus as claimed in claim 2, wherein theparity check matrix comprises a first parity check matrix comprising afirst information word partial matrix and a first parity partial matrix,which is a dual diagonal matrix, and a second parity check matrixcomprising a second information word partial matrix and a second paritypartial matrix which is a unit matrix, and wherein the encoder generatesthe parity bits corresponding only to the columns having the degree of 1in the parity check matrix.
 4. The receiving apparatus as claimed inclaim 1, wherein the first decoder decodes the signal transmittedthrough the first layer from the LDM signal using a first LDPC decoder,and decodes the LDPC information word bits, corresponding to the signaltransmitted through the first layer, using a first Bose, Chaudhuri,Hocquenghem (BCH) decoder to generate information word bits transmittedthrough the first layer.
 5. The receiving apparatus as claimed in claim4, wherein the encoder encodes the LDPC information word bits,corresponding to the signal transmitted through the first layer, usingan LDPC encoder to generate the parity bits corresponding only to thepreset columns in the parity check matrix.
 6. The receiving apparatus asclaimed in claim 5, wherein the encoder encodes the information wordbits, transmitted through the first layer, using a BCH encoder togenerate BCH parity bits, and wherein the LDPC encoder encodes theinformation word bits transmitted through the first layer and the BCHparity bits to generate the parity bits corresponding only to the presetcolumns in the parity check matrix.
 7. The receiving apparatus asclaimed in claim 4, wherein the second decoder decodes the signalobtained by the removing to generate LDPC information word bits andparity bits, corresponding to a signal transmitted through the secondlayer, using the first LDPC decoder, and decodes the LDPC informationword bits, corresponding to the signal transmitted through the secondlayer, using the first BCH decoder to generate the information word bitstransmitted through the second layer.
 8. The receiving apparatus asclaimed in claim 4, wherein the second decoder decodes the signalobtained by the removing to generate LDPC information word bits andparity bits, corresponding to a signal transmitted through the secondlayer, using a second LDPC decoder, and decodes the LDPC informationword bits, corresponding to the signal transmitted through the secondlayer, using a second BCH decoder to generate the information word bitstransmitted through the second layer.
 9. A decoding method of areceiving apparatus receiving and processing a layered divisionmultiplexing (LDM) signal, the decoding method comprising: decoding asignal transmitted through a first layer from the LDM signal using aparity check matrix to generate low density parity check (LDPC)information word bits and parity bits; encoding the LDPC informationword bits, generated by decoding the signal transmitted through thefirst layer, using the parity check matrix to generate parity bitscorresponding only to preset columns in the parity check matrix; anddecoding a signal obtained by removing, from the LDM signal, a signalcorresponding to the LDPC information word bits generated by decodingthe signal transmitted through the first layer, the parity bitsgenerated by the encoding, and the parity bits generated by the decodingexcept the parity bits generated by the encoding, thereby to generateinformation word bits transmitted through a second layer.
 10. Thedecoding method as claimed in claim 9, wherein the preset columns arecolumns having a degree of 1 in the parity check matrix.
 11. Thedecoding method as claimed in claim 10, wherein the parity check matrixcomprises a first parity check matrix comprising a first informationword partial matrix and a first parity partial matrix, which is a dualdiagonal matrix, and a second parity check matrix comprising a secondinformation word partial matrix and a second parity partial matrix,which is a unit matrix, and wherein the preset columns have the degreeof 1 in the parity check matrix.
 12. The decoding method as claimed inclaim 9, wherein the decoding the signal transmitted through the firstlayer from the LDM signal comprises: generating the LDPC informationword bits and the parity bits, corresponding to the signal transmittedthrough the first layer, using a first LDPC decoder; and decoding theLDPC information word bits, corresponding to the signal transmittedthrough the first layer, using a first Bose, Chaudhuri, Hocquenghem(BCH) decoder to generate information word bits transmitted through thefirst layer.
 13. The decoding method as claimed in claim 12, wherein thegenerating the parity bits corresponding only to the preset columnscomprises encoding the LDPC information word bits, corresponding to thesignal transmitted through the first layer, using an LDPC encoder togenerate the parity bits corresponding only to the preset columns in theparity check matrix.
 14. The decoding method as claimed in claim 13,wherein the generating the parity bits corresponding only to the presetcolumns comprises: BCH encoding the information word bits transmittedthrough the first layer to generate BCH parity bits; and encoding theinformation word bits transmitted through the first layer and the BCHparity bits to generate the parity bits corresponding only to the presetcolumns in the parity check matrix.
 15. The decoding method as claimedin claim 12, wherein the decoding the signal obtained by the removingcomprises: generating LDPC information word bits and parity bits,corresponding to a signal transmitted through the second layer, usingthe first LDPC decoder; and decoding the LDPC information word bits,corresponding to the signal transmitted through the second layer, usingthe first BCH decoder to generate the information word bits transmittedthrough the second layer.
 16. The decoding method as claimed in claim12, wherein the decoding the signal obtained by the removing comprises:generating LDPC information word bits and parity bits, corresponding toa signal transmitted through the second layer, using a second LDPCdecoder; and decoding the LDPC information word bits, corresponding tothe signal transmitted through the second layer, using a second BCHdecoder to generate the information word bits transmitted through thesecond layer.